William Brewster was one of the key figures in the Mayflower story as the spiritual leader of the colony.  He was a signatory to the Mayflower Compact.

Brewster was educated in both Greek and Latin and spent some time at Cambridge University, although he never completed a full degree.  Cambridge was a centre of thought concerning religious reformism.  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 was removed as Secretary of State by Queen Elizabeth, Brewster worked himself into his father's postmaster duties and maintained Scrooby Manor.  He was instrumental in establishing a 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 Holland in 1608.  Brewster became the church's Elder, responsible for seeing that the congregation's members carried themselves properly, both helping and admonishing them when necessary.

While in Leiden, Brewster and some others, began working a printing press and publishing religious books and pamphlets that were then illegally transported and distributed into England.  He also worked at the University of Leiden teaching students English.  By 1618, the English authorities had found otu about his printing press, and ordered the Dutch authorities to shut it down.  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 of settlers to set up a colony, their pastor John Robinson decided to remain behind with the majority of the congregation, intending to join them later.  The group that went on the Mayflower needed a sound church official, which was to be Brewster.  He took 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. His estate inventory lists the titles of several hundred books that he owned.  Shortly after he died, William Bradford wrote a short but concise biography of Brewster in his history Of Plymouth Plantation, though he erroneously filed it under 1643 instead of 1644.