The chief focus of Trevor's career, however, was his tenure as Surveyor and Rigger of the Navy, to which he was appointed in 1598. Whilst the official remuneration for this post was a mere £145 6s. 8d. a year, Trevor took advantage of the many opportunities to augment this, which doubtless provided him with his largest source of income until his resignation in 1611.
That Trevor was in high favour at court is evident from the honours and appointments showered on him at that time. In 1603 alone, he was knighted by King James I at the Tower of London, he was granted the office of Steward and Receiver at Windsor Castle, he was appointed Keeper of Upnor Castle and also Keeper of the house and royal park of Oatlands (where Trevor lived for much of the rest of his life).[2] He was also a Gentleman Usher of the Privy Chamber by 1603 and a Gentleman of the Privy Chamber from 1625.