William Monson was born in Lincolnshire, England, in the 1560s, the son of Sir John Monson (d. 1593) and his wife Jane. He and his brothers, Thomas and John, were raised in the Roman Catholic faith. William attended Oxford's Balliol College. His naval career began in 1585, when he joined the crew of a privateering vessel bound for Spain, and shortly thereafter, he took charge of several small vessels. In 1589, he traveled to the Canary and Azores Islands as the Earl of Cumberland's vice admiral, and in 1591 was promoted to flag captain. Spanish forces imprisoned him in Lisbon between 1591 and 1593, and, in 1596, he joined the service of Queen Elizabeth I. Monson won his own command in 1602. Following a distinguished career, he was imprisoned in the Tower of London for several months as a suspect in the 1616 murder of Sir Thomas Overbury. Following his release, he became a government consultant on the subject of fisheries and began to compose his six naval tracts. In 1637, he returned to public service as a member of the Council of War. He and his wife, Dorothy Wallop, had five children. He died on February 13, 1643.