In 1833 he spent his mornings at a day school run by the Revd Thomas Dale of St Matthew's Chapel, a Church of England establishment in Denmark Hill. In 1836 he attended lectures at King's College, where Dale had become the first professor of English literature. In October of that year he enrolled at Christ Church. At Oxford University he wrote a series of essays linking architecture and nature for Loudon's Architectural Magazine.

Ruskin was an extremely shy man and made few friends at university. However, he did develop good relationships with two fellow students, Charles Thomas Newton and Henry Acland. Ruskin spent most of his time reading books and writing and in 1839 won the Newdigate Poetry Competition. Ruskin had the pleasure of meeting one of his heroes, William Wordsworth, when presented with the prize.

Ruskin had developed an adolescent passion for the daughter of his father's partner, Pedro Domecq. Adèle, was the subject of much of Ruskin's youthful poetry. She was only fifteen when he first fell in love with her and was devastated when he learned of her engagement. In April 1840, shortly after Adèle's marriage, Ruskin suffered a mental breakdown. After two years of rest he returned to Oxford University where he achieved the unusual distinction of an honorary double fourth, taking his MA in October 1843.

Ruskin took a keen interest in art and at university gained a reputation as a skilled water-colourist. He wrote that he had "a sensual faculty of pleasure in sight, as far as I know unparalleled." Robert Hewison has argued: "Ruskin's perceptual sensibility, and his ability to deploy it both as a draughtsman and a visual analyst, marks him out from his more book-bound peers... although his drawings would justify the appellation, he never considered himself an artist, emphasizing always that he drew in order to gain certain facts, and he exhibited rarely. None the less, Ruskin's drawings are a remarkable achievement, both as a record of his mind, and as works of great beauty. His ability visually to depict architecture and landscape was matched by his genius for the verbal description of works of art."

Ruskin developed a great passion for the work of J. M. W. Turner. Soon after graduating he met Turner and began purchasing his work. In 1842 Ruskin and his father became patrons as well as collectors, when Turner's dealer Thomas Griffith included them in an invitation to Turner's circle of patrons to commission finished watercolours based on preliminary sketches. Later that year Ruskin read a newspaper review of that year's Royal Academy Exhibition, attacking Turner's contributions. Ruskin was furious and wrote that he was "determined to write a pamphlet and blow the critics out of the water".

Ruskin's father offered to support him financially in this venture and he eventually decided to write a series of books on modern art. The first volume of Modern Painters: their Superiority in the Art of Landscape Painting to the Ancient Masters, appeared in 1843. Ruskin wrote that "There is a moral as well as material truth - a truth of impression as well as of form - of thought as well as of matter." The author of John Ruskin (2007) has explained: "Such truths depended on a clarity of perception that was free of the pictorial conventions of the seventeenth-century Italian and Dutch masters who set the norm for received taste in landscape painting... Ruskin substituted a different way of seeing, that of the geologist and botanist, deploying the accuracy of observation encouraged by the classificatory sciences that did not conflict with natural theology."

In the book, Ruskin boldly proclaimed "the superiority of the modern painters to the old ones" and eulogized about the work of his great hero, J. M. W. Turner. The art critic, Patrick Conner, has pointed out: "Ruskin was scathing in his analysis of many of the established masters of the seventeenth-century painting, but won respect nevertheless for his acute observation of nature and for his lyrical evocations of Turner's art." After reading the book, Charlotte Bronte wrote: "I feel now as if I had been walking blindfold - this book seems to give me eyes." Ruskin also received support from William Wordsworth and Elizabeth Gaskell, who claimed that Ruskin was "no ordinary man". However, Ruskin's challenge to an aesthetic orthodoxy derived from Sir Joshua Reynolds drew strong disapproval from John Eagles in Blackwood's Magazine (October 1843) and from George Darley in The Athenaeum (February 1844).

In 1845 Ruskin spent time in Italy studying the work of the fourteenth and fifteenth-century artists of Pisa, Florence and Venice. It was these artists, together with Fra Angelico and Jacopo Tintoretto, who were the heroes of the second volume of Modern Painters (1846). Ruskin attempted to show that truthful perception of nature led to an experience of beauty that was also an apprehension of God. Ruskin divided beauty into two categories, "vital" and "typical’. According to Robert Hewison: "Vital beauty, in accordance with natural theology, expresses God's purpose in the harmonious creation of the world and its creatures, including man. Typical beauty, in accordance with evangelical typology, expresses the immanence of God in the natural world through the presence of ‘types’ to which man responds as beautiful. These types are qualities rather than things: infinity, unity, repose, purity, and symmetry. They are associated with divine qualities and can be found in nature and in art, but though abstract themselves, they have a real presence that it is the artist's duty truthfully to represent. Through his mother's training and the sermons he heard every Sunday, Ruskin had absorbed the evangelical practice of treating objects as both real and symbolic at the same time, a key critical practice that remained a feature of his writings throughout his life." Virginia Woolf later argued: "The style in which page after page of Modern Painters is written takes our breath away. We find ourselves marvelling at the words, as if all the fountains of the English language had been set playing in the sunlight for our pleasure, but it seems scarcely fitting to ask what meaning they have for us."

Ruskin met Effie Gray in October, 1847. He fell in love with the nineteen year-old and on his return to London, he wrote to George Gray asking to marry his daughter. Ruskin's parents raised no objections to the marriage, but preparations for the wedding in the following year were marred by Gray's near bankruptcy as a result of railway speculation. The wedding took place at Bowerswell House on 10th April 1848.

Effie later wrote to her father explaining that her marriage had not been consummated. "He alleged various reasons, hatred to children, religious motives, a desire to preserve my beauty, and, finally this last year he told me his true reason... that he had imagined women were quite different to what he saw I was, and that the reason he did not make me his wife was because he was disgusted with my person the first evening 10th April." Robert Hewison has argued: "This has been interpreted as meaning that Ruskin was equally innocent, especially in the matter of female pubic hair, but this seems unlikely, as he had seen erotic images belonging to fellow undergraduates at Oxford. There is also speculation that Effie's menstrual cycle interfered with consummation, which is plausible but not provable."

Ruskin admitted that he loved Effie passionately when he met her for the first time in 1840. After they were married he wistfully told her that "the sight of you, in your girlish beauty, which I might have had." As Suzanne Fagence Cooper, the author of The Passionate Lives of Effie Gray, Ruskin and Millais (2012) has pointed out: "John Ruskin loved young girls, innocents on the verge of womanhood. He became enchanted with twelve-year-old Effie when she visited Herne Hill in the late summer of 1840. The next time he saw her, John Ruskin felt she was 'very graceful but had lost something of her good looks'. After he had won her hand in 1847 and she was still only nineteen... Effie was too old to be truly desirable."

After returning from their honeymoon they lived at Denmark Hill and at a rented house at 31 Park Street, Mayfair. During this period John Ruskin was working on his book, The Seven Lamps of Architecture. Published in May 1849, the book was illustrated with fourteen plates drawn and etched by him. Ruskin attempted to draw the attention of the public to the merits of pre-Renaissance Italian architecture, and thereby broaden the scope of the Gothic Revival in Britain.

Effie Ruskin was unhappy with the state of her marriage and in February 1849, she returned to her parents in Perth and did not see her husband for nine months. In September Ruskin somewhat reluctantly travelled north to collect her. Three weeks later they set out for Venice. On their return to London their social and intellectual circle began to grow. This included Charles Eastlake, president of the Royal Academy and director of the National Gallery, and Frederick Denison Maurice, the leader of the Christian Socialist movement. Another friend was the poet, Coventry Patmore, who introduced him to members of the Pre-Raphaelite Brotherhood (PRB).

In 1851 Ruskin published the first volume of The Stones of Venice. According to the art historian, Patrick Conner: "These books exerted a fundamental influence on Victorian attitudes to architecture... Ruskin... exemplified his conception that a work of art reflects the personality of its creator - and in the case of architecture, a collective personality or age-spirit, whose growth, health and decay could be traced even in the smallest details of architectural decoration."

On the 7th May, 1851, The Times accused three members of the Pre-Raphaelite Brotherhood: John Everett Millais, William Holman Hunt and Charles Allston Collins of “addicting themselves to a monkish style”, having a “morbid infatuation” and indulging in “monkish follies”. Finally, the works are dismissed as un-English, “with no real claim to figure in any decent collection of English painting.” Six days later John Ruskin had a letter published in the newspaper, where he came to the defence of the Pre-Raphaelite Brotherhood. In another letter published on 30th May, Ruskin claimed that PRB “may, as they gain experience, lay in our land the foundations of a school of art nobler than has been seen for three hundred years”.

Ruskin now published a pamphlet entitled, Pre-Raphaelitism (1851). He argued that the advice he had given in the first volume of Modern Painters had “at last been carried out, to the very letter, by a group of young men who... have been assailed with the most scurrilous abuse... from the public press.” Aoife Leahy has argued: "Ruskin’s defences had now taken a new and decidedly evangelical tone. He had formed friendships with the Pre-Raphaelite artists on the basis of his letters to The Times and, just as significantly, he had been personally harassed by members of the public for his views."

John Ruskin became a close friend of John Everett Millais and agreed that Effie Ruskin should pose as the freed Jacobite prisoner's wife, in the painting, The Order of Release, 1746 (1853). Later that year Ruskin invited Millais and William Holman Hunt to go on holiday with them to Scotland. Hunt refused but Millais accepted the offer. In July they stayed in a rented cottage near Stirling. During their stay, Millais began painting portraits of Effie and Ruskin.

In November, Ruskin went on to lecture in Edinburgh whereas Millais returned to London. He had fallen in love with Effie and they continued to see each other over the next few months. On 25th April 1854 Ruskin accompanied his wife to King's Cross railway station to see her off on a visit to her parents in Scotland. That evening Ruskin was served with a legal citation at Denmark Hill, claiming the nullity of the marriage.

A medical examination confirmed Effie's virginity, but in a legal deposition that was not introduced in court, John Ruskin stated: "I can prove my virility at once." Robert Hewison has pointed out: "This was never put to the test, but it seems likely that Ruskin was referring to masturbation." He also told a male friend that he had been capable of consummating his marriage, but that he had not loved Effie sufficiently to want to do so." Following an undefended hearing in the ecclesiastical commissary court of Surrey on 15th July, the marriage was annulled on the grounds that "the said John Ruskin was incapable of consummating the same by reason of incurable impotency".

Ruskin wrote a letter to John Everett Millais stating that he wanted to remain friends. Millais replied: "I can scarcely see how you conceive it possible that I can desire to continue on terms of intimacy with you". Millais married Effie on 3rd July, 1855 and over the next few years she gave birth to eight children.

Ruskin was greatly influenced by the work of Thomas Carlyle. He agreed with his criticisms of the industrial revolution and in The Stones of Venice: Volume II (1853) Ruskin argued that the working man had been reduced to the condition of a machine: "We have much studied and much perfected, of late, the great civilized invention of the division of labour; only we give it a false name. It is not, truly speaking, the labour that it divided; but the men; - divided into mere segments of men - broken into small fragments and crumbs of life; so that all the little piece of intelligence that is left in a man is not enough to make a pin, or a nail, but exhausts itself in making the point of a pin or the head of a nail. Now it is a good and desirable thing, truly, to make many pins in a day; but if we could only see with what crystal sand their points were polished, - sand of human soul, much to be magnified before it can be discerned for what it is - we should think that there might be some loss in it also. And the great cry that rises from our manufacturing cities, louder than their furnace blast, is all in very deed for this, - that we manufacture everything there except men; we blanch cotton, and strengthen steel, and refine sugar, and shape pottery; but to brighten, to strengthen, to refine, or to form a single living spirit, never enters into our estimate of advantages. And all the evil to which that cry is urging our myriads can be met only in one way: not by teaching nor preaching, for to teach them is but to show them their misery, and to preach at them, if we do nothing more than preach, is to mock at it. It can only be met by a right understanding, on the part of all classes, of what kinds of labour are good for men, raising them, and making them happy; by a determined sacrifice of such convenience or beauty, or cheapness as is to be got only by the degradation of the workman; and by equally determined demand for the products and results of healthy and ennobling labour." William Morris later recalled: "To some of us when we first read it, now many years ago, it seemed to point out a new road on which the world should travel".

Ruskin gave a series of lectures on J. M. W. Turner, Gothic Architecture and the Pre-Raphaelite Brotherhood in Edinburgh in 1853. The Edinburgh Guardian reported: "Mr Ruskin has light sand-coloured hair; his face is more red than pale; the mouth well cut, with a good deal of decision in its curve, though somewhat wanting in sustained dignity and strength; an aquiline nose; his forehead by no means broad or massive, but the brows full and well bound together; the eye we could not see… Mr Ruskin's elocution is peculiar; he has a difficulty in sounding the letter ‘r’; but it is not this we now refer to, it is the peculiar tone in the rising and falling of his voice at measured intervals, in a way scarcely ever heard except in the public lection of the service appointed to be read in churches. These are the two things with which, perhaps, you are most surprised, - his dress and his manner of speaking, - both of which (the white waistcoat notwithstanding) are eminently clerical."

Despite his dispute with John Everett Millais, Ruskin continued to support the Pre-Raphaelites. In 1854 Ruskin wrote to The Times, praising the latest work of William Holman Hunt. This included The Light of the World (5th May) and The Awakening Conscience (25th May). Ruskin also pointed out the abilities of Dante Gabriel Rossetti. He also bought and commissioned drawings from Rossetti and his mistress, Elizabeth Siddal. Ruskin also encouraged his American friend Charles Eliot Norton, to buy Rossetti's paintings.

The art critic, Patrick Conner, has argued that Ruskin's writings inspired artists such as William Morris and Edward Burne-Jones: "Ruskin... proved an inspiration to William Morris and Edward Burne-Jones, whose enthusiasm carried Pre-Raphaelite principles into many branches of the decorative arts. They inherited from Ruskin a hostility to classical and Renaissance culture which extended to the arts and design of their own time. Ruskin and his followers believed that the nineteenth century was still afflicted by a demand for mass-production... They opposed themselves to mechanized production, meaningless ornament and anonymous architecture of cast iron and plate glass."

Ruskin became interested in socialism. Between 1854 and 1858 he taught at the Working Men's College that had been founded by Frederick Denison Maurice, Charles Kingsley and Thomas Hughes in London. In his lectures Ruskin denounced greed as the main principle guiding English life. In books such as Unto the Last (1862) Essays on Political Economy (1862) and Time and Tide (1867), Ruskin argued against competition and self-interest and advocated a form of Christian Socialism.

In January 1858 Ruskin met John La Touche, a wealthy Irish banker. He became a regular visitor to La Touche's home in London and got to know his wife Maria and daughter, Rose La Touche. In his autobiography, Præterita: Outlines of Scenes and Thoughts Perhaps Worthy of Memory in My Past Life (1885), Ruskin wrote about his first meeting with Rose: "On presently the drawing room door opened, and Rosie came in, quietly taking stock of me with her blue eyes as she walked across the room; gave me her hand, as a good dog gives its paw, and then stood a little back. Nine years old, on 3rd January, 1858, thus now rising towards ten; neither tall nor short for her age; a little stiff in her way of standing. The eyes rather deep blue at that time, and fuller and softer than afterwards. Lips perfectly lovely in profile;--a little too wide, and hard in edge, seen in front; the rest of the features what a fair, well-bred Irish girl's usually are; the hair, perhaps, more graceful in short curl around the forehead, and softer than one sees often, in the close-bound tresses above the neck."

Ruskin gave Rose drawing lessons. Ruskin wrote letters to Rose and he kept her replies "wrapped in gold leaf, tucked inside his waistcoat, close to his heart." According to Ruskin's biographer, Robert Hewison: "By the autumn of 1861 Ruskin felt deeply drawn towards Rose, but that October she fell ill for the first time from the psychosomatic disorder (possibly the as yet unrecognized condition anorexia nervosa)... Ruskin's preference for daughter over mother may have caused some tension... He did not see Rose between the spring of 1862 and December 1865, though Mrs La Touche did not break off contact. Rose had further bouts of illness in 1862 and 1863. Like other men of his class and culture... Ruskin enjoyed the company of young girls... It was their purity that attracted him; any sexual feelings were sublimated in the playful relationship of master and pupil that characterized his letters to several female correspondents."

Ruskin's father died on 3rd March 1864. His inheritance was £157,000, pictures worth at least £10,000, and property in the form of houses and land. Ruskin believed it was wrong to be a socialist and rich and he donated a great deal of his money to causes such as the St George's Guild in Paddington, the Whitelands College in Chelsea and the John Ruskin School in Camberwell.

In January, 1866, Ruskin, aged forty-six, proposed marriage to nineteen year old, Rose La Touche. She did not reject Ruskin but asked him to wait for three years. John La Touche and his wife were opposed to the marriage and Ruskin was only able to communicate with Rosa by using intermediaries, such as George MacDonald, Georgiana Cowper and Joan Agnew.

On 7th January, 1870, Ruskin met Rose accidentally at the Royal Academy. Rose, who was now 23 years old, began to see Ruskin on a regular basis. John and Maria La Touche became increasingly concerned about the possibility that her daughter might marry Ruskin. In October, 1870, Marie wrote to Effie Millais seeking evidence of Ruskin's impotence in order to stop the marriage. Effie confirmed this and stated that Ruskin was "utterly incapable of making a woman happy". She added that "he is quite unnatural... and his conduct to me was impure in the highest degree." She ended her letter by saying, "My nervous system was so shaken that I never will recover, but I hope your daughter will be saved."

John Everett Millais became concerned about the impact that this correspondence was having on his wife. He wrote to Rose's parents begging them to leave his wife alone. He insisted that "the facts are known to the world, solemnly sworn in God's house" and asked why this "indelicate enquiry necessary". Millais then went on to argue that Ruskin's "conduct was simply infamous, and to this day my wife suffers from the suppressed misery she endured with him." Millais feared that a consummated marriage with Rose would render the previous grounds for annulment void, and would make his marriage to Effie bigamous.

In July 1871 Rose La Touche broke off her relationship with Ruskin. Shocked by the news, he suffered a mental breakdown while staying Matlock Bath in Derbyshire. Rosa's health was also deteriorating. In an effort to help her recover, they gave permission for Ruskin to visit her at their estate in Harristown, County Kildare. In January 1875, she returned to London, but extremely ill, and Ruskin saw her for the last time on 15th February, before she was taken to Dublin in April. Rose died on 25th May, aged twenty-seven. Suzanne Fagence Cooper, the author of The Passionate Lives of Effie Gray, Ruskin and Millais (2012), has pointed out that "she died of anorexia, or brain fever, or a broken heart, depending on which account you believe". Ruskin later wrote: "Rose, in heart, was with me always, and all I did was for her sake."

In 1871 Ruskin began publication of Fors Clavigera: Letters to the Workmen and Labourers of Great Britain. He wrote: "Whose fault is it, you cloth-makers, that any English child is in rags? Whose fault is it, you shoemakers, that the street harlots mince in high-heeled shoes and your own babies paddle bare-foot in the street slime? Whose fault is it you bronzed husbandmen, that through all your furrowed England, children are dying of famine?" Ruskin blamed the capitalist system for these problems. Between 1871 and 1878 it was issued in monthly parts. Ruskin intended the work to be a "continual challenger to the supporters of and apologists for a capitalist economy". It was Ruskin's socialist writing that influenced trade unionists and political activists such as Tom Mann and Ben Tillett.

Ruskin suffered a complete mental breakdown in February 1878. He later wrote to a friend, Charles Eliot Norton: "Mere overwork or worry, might have soon ended me, but it would not have driven me crazy. I went crazy about St Ursula and the other saints." It has been noted that "Ruskin's delusions during his first attack of what has been characterized as either manic depression or paranoid schizophrenia." Ruskin retreated to his home at Brantwood, across the lake from the village of Coniston.

Despite several bouts of mental illness, Ruskin was able to complete The Art of England in 1884. This was followed by The Storm Cloud of the Nineteenth Century (1885). He also began work on his autobiography, Præterita: Outlines of Scenes and Thoughts Perhaps Worthy of Memory in My Past Life. His biographer, Robert Hewison, has commented: "Praeterita is a delightful work, a rewriting of Ruskin's life that makes it unreliable as a source of biographical fact, yet an accurate portrait of the author's mind. That it remained unfinished shows that the contradictions of that mind never achieved their desired synthesis, though this version is the best that could be achieved, and makes it a significant work of literature, most especially in his Wordsworthian evocation of the power of nature on the growth of a young mind. The conscious manipulation of memory had been intended to be therapeutic, but there were memories and hurts that could not be suppressed, and as Ruskin struggled to bring them out he found himself fighting a double battle: to retain his sanity, and to control the composition of the work."

At the end of July 1885, just as the first two sections of Præterita describing his family background and early childhood appeared, Ruskin had a fourth, longer, and more severe attack of madness. He attempted to finish his autobiography but had only reached 1858, the year when he met Rose La Touche, when he was forced to abandon the project after suffering another serious breakdown. He gradually retreated into silence, saying little, and writing few letters.

John Ruskin died of influenza on 20th January, 1900.