Samuel Sewall was born at Bishop Stoke, Hampshire, England on March 28, 1652. In 1661, Sewall came with his family to settle in Newbury, Mass. Ten years later he graduated from Harvard. Sewall married Hannah Hull, the daughter of one of the wealthiest men in the colony, in 1676 and began a career as a merchant. In 1681, Sewall was appointed by the General Council to run the printing press. Sewall used his position to publish articles of his own and achieve greater notoriety. From 1691 to 1725 Sewall served on the Governor's Council.

Governor Phips appointed Sewall to the Court of Oyer and Terminer on May 27, 1692. Sewell's diary entries provide important information about the Salem witch trials. The diary entries reveal little personal reservations or remorse concerning his own role in the conduct of the trials. In December 1696, however, Sewall wrote a proclamation for a day of fast and penance and reparation by the government for the sins of the witchcraft trials. Sewall publicly apologized for his role in the trials.  Each year after 1697 Sewall set aside a day in which he fasted and prayed for forgiveness for his sins in the Salem trials.

Though his role in the Salem trials brought Sewall infamy, he continued to receive notoriety for his 1700 publication of The Selling of Joseph. Considered the first anti-slavery piece published in the colonies, The Selling of Joseph presents religious arguments against slavery. Countering the prevailing social theory of the time, Sewall argues all men are created equal, using examples to prove his argument. Never one to adhere to prevailing social norms, Sewall adamantly opposed wearing then-fashionable white powder wigs and never conceded this position.

Sewall died on January 1, 1730 at his Boston home.