According to B.R. White, Fruin was an elder at Dymock (Dimmock), Gloucestershire in 1653. He seems to have been called to Warwick in the 1680s, and represented the church at the 1689 Assembly. In 1690, he was asked to preach upon trial for the eldership at the new church in Bampton, Devon, though he was not called as its first pastor.