 Vernon was educated at Westminster School and at Trinity Hall, Cambridge, proceeding MA in 1755.He served as a Whig Member of Parliament for Weobley from 1757 to 1761, Bramber from 1762 to 1768 and Glamorganshire from 1768 to 1780.His first wife was Louisa Barbara Mansel, daughter of Bussy Mansel, last Baron Mansel of Margam.