[1] Profiting from family influence, active commissions in the American War of Independence and a keen sense of seamanship and aggressive tactical awareness, promotion came easily.

[1] He was then in a good position to profit from the mass promotions that accompanied the outbreak of the French Revolutionary War in 1793, being made a post-captain on 16 May 1793 in the small frigate HMS Tartar.

[1] During the siege, Nelson lost an eye and Fremantle gained a reputation for daring, taking his ship under the fortress walls despite heavy fire from above which had already sunk one frigate in the bay.

The following year Fremantle commanded the frigate HMS Inconstant and was engaged in Lord Hotham's indecisive and cautious fleet action in the Gulf of Genoa on 14 March 1795.

[1] While convalescing at home, Fremantle honed his theories of successful command at sea, shown by several proposals he sent to the Admiralty concerning the judgement of petty disciplinary actions on board ship.

Relatively undamaged, Neptune was able to tow the shattered Victory back to Gibraltar and Fremantle profited by taking the chapel silver from the big Spanish ship, which he used to adorn his home.

Fremantle spent the next five years in England, as a member of Parliament for Sandwich 1806–1807[2] and a Lord of the Admiralty (1806–1807), before being posted rear-admiral[3] and taking command in the Adriatic Sea, where he employed the frigate squadrons under him successfully against French-held Italy and Dalmatia.

For his services he was made a Knight Grand Cross of the Order of the Bath on 12 April 1815, as well as a baron of the Austrian Empire and later a vice-admiral[4] and, from 1818, the Commander-in-Chief, Mediterranean Fleet.