John Day was born in Cawston, Norfolk, and educated at Ely. In 1592 he became a sizar of Caius College, Cambridge, but he was expelled in the next year for stealing a book. He became a playwright, collaborating on or authoring 22 plays. Little is known of his personal life outside of a description by Ben Jonson in 1618/19 as a "rogue" and a "base fellow." It is likely that he was the "John Daye, yeoman" who killed fellow dramatist Henry Porter in Southwark 1599, although if he did murder his colleague it did not interrupted his writing career. The date of his death is unknown, but an elegy on him by John Tatham was published in 1640.