He was born in London, the son of a judge. Educated at Oxford under John Colet and Thomas Linacre, he completed his legal studies at New Inn and Lincoln's Inn, was Reader for three years in Furnival's Inn, and spent the next four years in the Charterhouse in 'devotion and prayer'. During the last years of Henry VII he became Under-Sheriff of London and a member of parliament. Introduced to Henry VIII through Thomas Wolsey, he became Master of Requests (1514), Treasurer of the Exchequer (1521), and Chancellor of the Duchy of Lancaster (1525). He was Speaker of the House of Commons, and was sent on missions to the French courts of Francis I and Charles V.
On the fall of Wolsey in 1529, More, against his own strongest wish, was appointed Lord Chancellor. He executed his office with a primitive virtue and simplicity but displayed particular harshness in his sentences for religious opinions. He sympathized with John Colet and Erasmus in their desire for a more rational theology and for radical reform in the manners of the clergy, but like them he felt no promptings to break with the historic Church. He saw with displeasure the successive steps which led Henry to the final schism from Rome.
In 1532 he resigned the chancellorship. In 1534 Henry was declared head of the English Church and More's steadfast refusal to recognize any other head of the Church than the pope led to his sentence for high treason after a harsh imprisonment of over a year. Still refusing to recant, he was beheaded.
By his Latin Utopia (1516, Eng trans 1556), More takes his place with the most eminent humanists of the Renaissance. His History of King Richard III (1513) 'begins modern English historical writing of distinction', although it is actually a second-hand account taken from Richard's enemy, Archbishop John Morton. He was canonized in 1935. His feast day is 9 July.