Sir Thomas More (1478-1535) was an English lawyer, judge, philosopher, and humanist. He served as chancellor to King Henry VIII from 1529 to 1532, and he was a mentor and close personal friend to Henry. More was a devout Catholic who campaigned heavily against the Protestant Reformation that was sweeping through Europe. When he was a judge, he took action against booksellers who were circulating Protestant writings. These writings were, in pre-Reformation England, considered heresy, as they spoke out against the Catholic Church. During his time as chancellor, More was accused of using torture against prisoners to force them to confess to heresy. Though More denied these allegations in his lifetime, he also burned six people at the stake for heresy, demonstrating his hardline stance against Protestants. More was executed on July 6, 1535, for high treason against the King. In 1886, Pope Leo XIII beatified Thomas More; he was later canonized as a martyr by Pope Pius XI.

In A Man for All Seasons, More is a sympathetic protagonist whose intense commitment to his personal convictions guides his actions. Most other characters in the play are willing, at some point, to make compromises to ensure their own safety and prosperity; More is not.