James Cropper, the son of Thomas Cropper, a yeoman farmer, was born at Winstanley, in 1773. His family were members of the Society of Friends. He left home at the age of seventeen to work for Rathbone Brothers, in Liverpool. He later established his own mercantile house, Cropper, Benson & Company.

In 1796 Cropper married Mary Brinsmead. Over the next few years she had three children, They had two sons, John and Edward, and a daughter, Eliza, who later married Joseph Sturge.

According to his biographer, M. W. Kirby: "Cropper's trading links were initially with Ireland and North America, but by the end of the Napoleonic wars he was importing a wide range of products, including textiles and spices from India and China. Cropper, Benson & Co. also established the first line of packets to carry mail to North America. The company engaged in common trading ventures with Rathbone Brothers, extending to the joint ownership of vessels."

James Cropper was an early opponent of slavery. He supported the campaign of some members of the House of Commons, such as William Wilberforce, Samuel Romilly, William Dolben, Henry Thornton, Samuel Whitbread, Charles Middleton and William Smith to abolish the slave trade. To support their efforts he made up parcels of sugar and coffee from the East Indies and sent them to every MP to show that slave labour was not essential to their cultivation.

Under the terms of the Abolition of the Slave Trade Act (1807) British captains who were caught continuing the trade were fined £100 for every slave found on board. However, this law did not stop the British slave trade. If slave-ships were in danger of being captured by the British navy, captains often reduced the fines they had to pay by ordering the slaves to be thrown into the sea.

Some people involved in the anti-slave trade campaign such as James Cropper, argued that the only way to end the suffering of the slaves was to make slavery illegal. William Wilberforce disagreed, he believed that at this time slaves were not ready to be granted their freedom. He pointed out in a pamphlet that he wrote in 1807 that: "It would be wrong to emancipate (the slaves). To grant freedom to them immediately, would be to insure not only their masters' ruin, but their own. They must (first) be trained and educated for freedom."

Cropper remained concerned about the intentions of those who had opposed the anti-slave trade legislation. On 12th March 1822, he wrote to Thomas Clarkson noting that "on the abolition of the slave trade and the efforts of the British government to induce other governments to follow their example, there is some suspicion of a mixture of motive in the later part, nor can we wonder at it when we see the Assembly of Jamaica petitioning the King to use his influence to induce other countries to abolish it and at the same time petitioning against the introduction of East India sugar into this country."

In 1823 Cropper wrote to Zachary Macaulay suggesting the formation of a new abolition society. According to the author of The Great Abolition Sham: The True Story of the End of the British Slave Trade (2005): "Its strategy first and foremost would be to obtain information on the state of slavery in British and foreign colonies in the West Indies and in North and South America, in order to prove the argument that free labour was cheaper than slave labour but that the expense of cultivation would also be lessened by the amelioration of the hard treatment of slaves."

Later that year Thomas Clarkson, Joseph Sturge, Thomas Fowell Buxton, William Allen, and Zachary Macaulay to form the Society for the Mitigation and Gradual Abolition of Slavery. Clarkson agreed to take to the road again to resurrect the old abolition network of some 70 local bodies and to establish new ones. Cropper offered Clarkson £500 to pay for the campaign.

In his book, The Great White Lie (1973), Jack Gratus argues that: "The plan was to divide the country into districts, and to send a lecturer to each, armed with facts and information about slavery and fired by an enthusiasm to convert new audiences around the country to emancipation. The Quakers accepted the idea immediately and Cropper advanced £500 out of his own pocket. The prosperous Birmingham Quaker, Joseph Sturge, who was to play such an important role in the later history of emancipation, advanced £250. Wilberforce gave £20 and James Stephen ten guineas."

At the conference in May 1830, the Society for the Mitigation and Gradual Abolition of Slavery agreed to drop the words "gradual abolition" from its title. It also agreed to support Sarah Wedgwood's plan for a new campaign to bring about immediate abolition. The following year the Anti-Slavery Society presented a petition to the House of Commons calling for the "immediate freeing of newborn children of slaves".

Cropper was also a supporter of the railway industry. He became a director of the Liverpool and Manchester Railway Company. After several years of debate, Parliament gave permission for the Manchester & Liverpool Railway to be built in 1826. George Stephenson was faced with a large number of serious engineering problems. This included crossing the unstable peat bog of Chat Moss, a nine-arched viaduct across the Sankey Valley and a two-mile long rock cutting at Olive Mount.

The Liverpool & Manchester railway was 31 miles long and consisted of a double line of rails of the fish-bellied type and laid on stone or timber sleepers. Passenger trains started at the Crown Street Station in Liverpool and after passing Moorish Arch at Edge Hill terminated at Water Street in Manchester. The railway was opened on 15th September, 1830. It was a great success. In 1831 the company transported 445,047 passengers. Receipts were £155,702 with profits of £71,098.

In 1831 Cropper and his son-in-law, Joseph Sturge, formed the Young England Abolitionists, a pressure group within the Society for the Abolition of Slavery, that campaigned for a new act of Parliament. It was distinguished from other anti-slavery groups by its unconditional arguments and vigorous campaigning tactics. Peter Archer has argued that they directed "their activities much more in the direction of forming mass opinion."

The Abolition of Slavery Act was passed on 28th August 1833. Cropper was disappointed by the measure that granted compensation to slave owners and substituting a temporary system of unpaid apprenticeship for slavery. Sturge visited the West Indies (November 1836 to April 1837) where he collected evidence to demonstrate the flaws in the legislation. On his return he published The West Indies in 1837 and gave evidence for seven days before a committee of the House of Commons. As a result of his campaign in 1838 the apprenticeship system was terminated.

According to another biographer of Cropper: "Though the family were very rich, they attached little importance to material goods and followed a relatively simple way of life. Indeed, the subject of money never arose in the Cropper family. Their chief interest lay in leading a good Christian life which involved sharing their good fortune with their poorer brethren. They became widely known as a major charitable force in Liverpool.... Every year the family would entertain the boys from the training ship Akbar at Dingle Bank where games were organised and treats provided. They also set up a ragged school which provided teaching in moral and elementary education to pauper children."

James Cropper died on the 26th of February 1840.