[1] Fitzgerald joined the Royal Navy in March 1786 as a midshipman on board the frigate HMS Winchelsea commanded by Edward Pellew.
[2] He bombarded Le Havre while in a squadron commanded by Sir Richard Strachan before taking part in the action of 30 May 1798, where he assisted in destroying the French 36-gun corvette Confiante.
[8][2] After the Peace of Amiens ended on 18 May 1803 Fitzgerald looked to continue his naval service, but issues with his health meant that he was unable to secure an appointment at sea.
[2] Instead Fitzgerald was assigned as senior officer of the Sea Fencibles on the Isle of Wight, and commanded the naval district between Kidwelly and Cardigan in Wales.
[2] In July 1816 the Commissioners of the Navy attempted to elect Fitzgerald to the position of Governor of the Royal Naval Asylum, a large school.
In January 1835 Fitzgerald was made a Knight Commander of the Royal Guelphic Order, and in November 1840 was restored to the navy list with the rank of vice-admiral of the blue.