Gloucester was born in 1776 as a slave in Tennessee. He arrived in Philadelphia in 1807. He began preaching at a house on Gaskill Street. His congregation grew and eventually moved to the corner of 7th and Shippen (now Bainbridge) Streets. The First African Presbyterian Church was built and dedicated on this spot in May 1811. Gloucester preached his first official sermons to a congregation of 123 people. He served the church until his death in 1822.