Trevor’s father made precise provision in his will for his education and he was to be ‘ordered’ by Robert Sackville, Lord Buckhurst’s heir. While Trevor was at the Inner Temple two cf his brothers entered the service of Charles Howard I, the lord admiral, and Trevor himself followed their example, certainly by October 1604. Meanwhile, in 1601 he had been returned to Parliament for Tregony through the influence of his brother John’s wife’s family, the Trevanions. It was probably John who was the Mr. Trevor mentioned in the journals of this Parliament.3J. Whitelocke, Liber Famelicus (Cam. Soc. lxx), 103; PCC 64 Leicester; EHR, lix. 360; HMC Hatfield, xvi. 335; xvii. 347.
Though a contemporary held Trevor to be ‘no great lawyer’ he served as a judge throughout Charles’s reign, achieving some notoriety for his defence of ship money and for his condemnation of John Hampden, a relative, for refusing to pay it. He resigned from the bench after the King’s execution and retired to his estate at Leamington Hastings, where he died, aged about 84, 21 Dec. 1656, having outlived his three wives. His only son and heir, Thomas, also represented Tregony in Parliament, and was created a baronet, the title dying with him.4PCC 8 Ruthen; Dugdale, Warws. i. 318-19.