Watts Phillips, the second son of Thomas Phillips and his wife, Esther Ann Watts, was born at Robert Street, Hoxton, on 16th November 1825. His father was an upholsterer and timber merchant. A talented artist he was apprenticed to George Cruikshank as a young man. While working with Cruikshank he got to know Douglas Jerrold and Mark Lemon.
Phillips studied art in Paris but the 1848 French Revolution drove him to Brussels. He returned to London in 1849 and for a while worked for the publisher David Bogue. On 7th June 1851 he married Mary Elizabeth Mariner, the daughter of a stockbroker.
Watts Phillips provided cartoons for several journals using the name "The Ragged Philosopher". He also wrote The Wild Tribes of London (1855), an account of the London slums. In 1857 his play Joseph Chavigny was accepted by Benjamin Webster. It was produced at the Adelphi in May, with Webster playing the leading role. This was followed by the play, The Poor Strollers .
Charles Dickens accused Phillips of plagiarism, when his play, The Dead Heart , was produced for the first time on 10th November 1859. This was seven months after the first episode of A Tale of Two Cities had appeared in All the Year Round . It had the same historical setting, much the same story and approximately the same climax. However, Joseph Knight, the drama critic of the The Athenaeum, discovered that Benjamin Webster had given the play to Dickens read during a visit by the novelist to Brighton early in 1857. As Knight pointed out: "If anything Dickens was indebted to Phillips's play for some crucial features of his novel, most notably a last-minute heroic substitution of one character for another at the guillotine during the French Revolution."
The New York Times reported that: "The great impression on the public made by his drama of The Dead Heart caused Mr. Benjamin Webster to secure his services specially for the Adelphi, but eventually other establishments in London were furnished by the now popular dramatist with some of their most attractive novelties."
Phillips had left his wife during this period. According to Phillips she "made my life a misery on account of her ungovernable and most wicked temper". Phillips mistress, Caroline Huskisson, was living in Paris. They had four children: Gordon Watts (1859), Mary Roland (1860), Fairfax Balfour (1861) and Leslie Latimer. His will aimed to protect Caroline and their children, "and to prevent any portion of" his property "falling into the hands of the woman Elizabeth Phillips known as Lilly Phillips and of her child Basil of whom I am not the father and also of any other children she has had or may have by other men."
Other plays by Phillips included Paper Wings (1860), His Last Victory (1862), A Woman in Mauve (1865), The Huguenot Captain (1866), Lost in London (1867), Nobody's Child (1868), Maud's Peril (1868) and Amos Clark (1872). He also contributed articles for The Daily News.