Thomas Talfourd, the son of Edward Talfourd, a brewer, and his wife, Ann Nood Talfourd, was born at Reading, Berkshire, on 26th May 1795. After studying with private tutors he was educated at the recently founded protestant dissenters' grammar school in Mill Hill (1808–10) before transferring to a local grammar school (1810–12), where he became head boy. It has been claimed that Talfourd was deeply influenced by his headmaster, Dr Richard Valpy, who encouraged his enthusiasms for literature and for good causes.

Talfourd's family's economic circumstances meant that he could not attend university. On the advice of Henry Brougham he decided on a legal career. In 1813 he joined the chambers of Joseph Chitty in the Inner Temple. He continued his interest in literature and his play, Freemasonry, or, More Secrets than One , was performed in 1815. Talfourd also became involved in politics and on 19th October 1819, he gave a passionate speech in defence of the right of public assembly, in protest against the Peterloo Massacre.

In 1821 Talfourd was called to the bar and joined the Oxford circuit and Berkshire sessions. According to his biographer, Edith Hall: "In 1822 he contracted a happy marriage to Rachel, eldest daughter of John Towill Rutt, a nonconformist minister. She was fiercely unfashionable and regarded as a lovable eccentric. They had several children; Talfourd was heartbroken in 1824 by the death in infancy of their first child, a son, and by the death of another son, Charles (named after Lamb), in 1837. But he was devoted to Mary and Kate, their daughters, and especially to Francis (Frank) Talfourd (1828–1862), their surviving son."

Talfourd reported on legal cases for The Times and contributed essays to The New Law Journey and The New Monthly Magazine. He also wrote about drama and literature in The Edinburgh Review. During this period he became friends with Charles Lamb, Douglas William Jerrold, William Makepeace Thackeray, William Macready, Daniel Maclise and John Forster. The novelist, Charles Dickens, was a regular visitor to the Talfourd home. He recalled: "If there ever was a house… where every art was honoured for its own sake, and where every visitor was received for his own claims and merits, that house was his... Rendering all legitimate deference to rank and riches, there never was a man more composedly, unaffectedly, quietly, immovable by such considerations... On the other hand, nothing would have astonished him so much as the suggestion that he was anyone's patron."

On 7th January, 1835, Talfourd was elected to represent Reading in the House of Commons. He was on the left-wing of the Liberal Party and was a leading campaigner for universal male suffrage and an end to the slave trade. Talfourd was also in favour of women's rights and was responsible for The Infant Custody Act (1839) that gave the court discretion to award custody of children under seven years of age to the mother in cases of separation or divorce, provided she was not guilty of adultery.

Talfourd continued to write plays and his poetic tragedy Ion , was first performed at the Covent Garden Theatre, on his birthday, 26th May 1836. According to his biographer, Edith Hall: "Written in blank verse, it is an idiosyncratic combination of Romantic utopian Hellenism derived from Shelley with nonconformist religiosity, especially articulated in the hero Ion's extreme altruism. Talfourd's advocacy of social reform was grounded in religious principles and presupposed moral and spiritual reform." In the North American Review (1837) Cornelius Conway Felton, professor of Greek literature at Harvard University, declared it a masterpiece, and it was often revived in the American commercial theatre.

Encouraged by writers such as Charles Dickens, William Makepeace Thackeray and William Wordsworth, he campaigned for a new Copyright Act. This was designed to enable the dependants of authors to profit from the sales of their writings after their deaths. Dickens was so pleased with his efforts that he dedicated The Pickwick Papers (1837) to Talfourd.

Caroline Norton wrote a pamphlet explaining the unfairness of the law entitled The Natural Claim of a Mother to the Custody of her Children as affected by the Common Law Rights of the Father. Caroline argued that under the present law, a father had absolute rights and a mother no rights at all, whatever the behaviour of the husband. In fact, the law gave the husband the legal right to desert his wife and hand over his children to his mistress. For the first time in history, a woman had openly challenged this law that discriminated against women. Norton now began a campaign to get the law changed. Talfourd agreed to Caroline's request to introduce a bill into Parliament which allowed mothers, against whom adultery had not been proved, to have the custody of children under seven, with rights of access to older children. The bill was passed in the House of Commons but was rejected by the House of Lords.

Talfourd eventually persuaded parliament to pass the 1842 Copyright Act. However, as Robert L. Patten, the author of Charles Dickens and his Publishers (1978) has argued, Charles Dickens was disappointed by the final legislation: "The 1842 Copyright Act, which Talfourd's friends at last succeeded in getting through a reluctant House, prolonged the copyright term to forty-two years, or seven years after the author's death, which gave some security to writers, but not so much as the French laws, where copyright passed to the widow for her life and to the author's children for twenty years thereafter."

Claire Tomalin has pointed out: "Although his name is hardly remembered now, Talfourd was an outstanding figure in his day, idealistic, hard-working and effective.... He had protesting against the Peterloo Massacre in 1819, supported universal male suffrage and the total abolition of slavery, steered through the bill giving divorced women custody of their young children, and was currently seeing through the 1842 Copyright Act that for the first time protected authors' earnings in England during their lifetimes and for a period after their death."

Talfourd retired from the House of Commons to become a judge in 1848. His biographer has argued: "Although not an outstanding judge, he is said to have exercised his responsibilities and duties with good humour, sound judgement, and unimpeachable integrity. His later life was blighted by anxieties caused by his son Frank's debts, failure to take his degree at Christ Church, Oxford, and half-hearted attempts to make a career in law."

Thomas Talfourd died after suffering an apoplectic seizure in Stafford on 13th March 1854.