William Brewster was born about 1566, the son of William Brewster. He was educated in both Greek and Latin and spent some time at Cambridge University, although he never completed a full degree. He went into the service of William Davison, then Secretary of State, while his father back home maintained a position as the postmaster of Scrooby, Nottinghamshire. Under Davison, Brewster first traveled to the Netherlands. After Davison's departure as Secretary of State, Brewster worked himself into his father's postmaster duties and maintained Scrooby Manor. Brewster was instrumental in establishing the small Separatist church with Richard Clyfton, and they often held their meetings in the Manor house. Brewster and the others were eventually found and forced out, and fleeing prosecution and persecution they headed to Amsterdam in 1608, and moving to Leiden, Holland in 1609. Brewster became the church's Elder, responsible for seeing that the congregation's members carried themselves properly, both helping and admonishing them when necessary.
In Leiden, Brewster working with Thomas Brewer became working a printing press and publishing religious books and pamphlets which were then illegally conveyed into England. Brewster also employed himself teaching University of Leiden students English. By 1618, the English authorities were onto him and his printing press, and had the Dutch authorities in pursuit of him. Thomas Brewer was arrested and held in the University of Leiden's prison, but Brewster managed to evade the authorities and went into hiding for a couple years.
When the Leiden church congregation decided to send the first wave to set up and establish a colony that everyone could eventually move to, their pastor John Robinson decided to remain behind in Leiden with the majority of the congregation, intending to come later. The smaller group that went on the Mayflower desired the next highest ranking church official, Elder Brewster, go with them; so he agreed. He brought his wife Mary and two youngest children, Love and Wrestling, on the Mayflower with him.
Brewster continued his work as Church Elder throughout his life at Plymouth Colony. His wife Mary died in 1627, and he never remarried. He lived to be nearly 80 years old, dying in 1644. Shortly after he died, William Bradford wrote a short but concise biography of Brewster, just a couple pages, in his history Of Plymouth Plantation.