Harrison, who was born at Kingston-upon-Hull, East Riding of Yorkshire, was taken by his parents, Richard Harrison and Margaret Picke Harrison, while a youth to New England, and there trained up to the ministry.
Thus Harrison's change of views occasioned his dismissal, upon which he came to London, and, obtaining some fame as a preacher, was chosen about 1650 to succeed Dr. Thomas Goodwin in his gathered church at St. Dunstan's-in-the-East.