In April 1766, he was rated able seaman aboard the Launceston: in May 1768, he was made lieutenant and moved into HMS Romney under the command of Sir Samuel Hood.
Although Inglefield returned to the Launceston in October, by July 1769, he was back with Hood aboard the Romney and from that time forward his career was closely associated with his friend's.
In August of the same year, Hood transferred him to HMS Centaur (74 guns), which Inglefield commanded in three actions against the French, culminating on 12 April 1782, at the Battle of the Saintes.
It was however aboard the Centaur that Inglefield suffered the most harrowing episode of his career when, sailing for England with the convoy under Rear-Admiral Sir Thomas Graves, his ship along with the others was struck by a hurricane.
Thrown upon her beam ends, dismasted in order to right herself and with her rudder gone, she eventually foundered despite the most strenuous efforts of Inglefield and the crew over several days.
A dramatic painting of the incident in which those on the pinnace, thrusting off from the foundering Centaur, pulled aboard a 15-year-old midshipman who had thrown himself from the wreck, was later made into a popular print.
Towards the end of 1794 he returned to England with Samuel, now Viscount, Hood and was thereafter a resident commissioner of the Navy Board, serving in Corsica, Malta, Gibraltar and Halifax, Nova Scotia.