Rowley entered the navy as a volunteer, serving under Captain, later Sir John, Norris. His career was undistinguished until 1741, when he joined the Mediterranean fleet, taking part in February 1744 in the engagement off Toulon in which he was one of the few flag-officers concerned whose conduct was not called into question. Appointed in August that year to the command of the Mediterranean fleet in succession to Thomas Mathews, he presided over a court martial which was conducted with extraordinary partiality to the officer concerned, the son of Sir John Norris.
Notwithstanding this affair Rowley was promoted to be admiral in 1747. In 1749 he was one of a number of admirals and captains who signed an address to the Admiralty against a new article of war subjecting half-pay officers to courts martial and were summoned to the Admiralty, where he spoke against the article.
I pitched upon him, not only from my own personal regard and friendship to him, but likewise from knowing that your Grace honoured him with your protection; and also from my hopes that ... it might not be disagreeable to the King to have him in Parliament.
Add. 32720, f. 90.
Next year he was appointed by the influence of Lord Granville to a seat on the Admiralty board.
He died 1 Jan. 1768.
