Fisher was sent to England to join the navy in 1854. After completing his training at HMS Britannia he was assigned as a cadet to HMS Calcutta, an old ship-of-the-line which was sent to assist in blockading Russian ports in the Gulf of Finland during the Crimean War. A few months later the ship returned to the UK where he was assigned to HMS Agamemnon, which arrived at Constantinople (now Istanbul) just as the war ended. Promoted to midshipman, he served on a corvette, HMS Highflyer, then the steam frigate HMS Chesapeake and finally the paddle sloop HMS Furious in the China Wars of 1859-1860.
He studied at HMS Excellent, the naval gunnery school, for 14 months before being transferred as gunnery officer to HMS Warrior, the first all-iron sea-going armoured battleship. He returned to Excellent in 1864 as an instructor where he remained until 1869. Whilst there he married Frances Broughton.
Following two and a half years as commander (i.e. second in command) of HMS Ocean, flagship of the China Station he returned to Excellent again in 1872, this time as head of torpedo and mine training, during which he split it off as HMS Vernon. From 1876 until 1883 he served as a captain, commanding five ships in succession, the last being HMS Inflexible. Inflexible was a very prestigious appointment, the most powerful warship of her day, although in practice the four huge muzzle-loaded guns took so long to load that she was almost useless for naval warfare. Nevertheless she was assigned to the Mediterranean fleet where she took part in the Egyptian War of 1882, bombarding the port of Alexandria as part of Admiral Seymour's fleet.
He returned to the UK to become commanding officer of Excellent in April 1883. He was Director of Naval Ordinance from 1886 until 1890, where he met with limited success in trying to wrest the design of naval guns from the War Office.
He was superintendant of the dockyard at Portsmouth for a few months in 1891-1892 after which he became Third Sea Lord, naval officer with overall responsibility for provision of ships and equipment. He presided over the development of torpodo boat destroyers, later shortened to destroyers, for countering torpedo boats. Torpedo boats had become a major threat as they were cheap but able to sink the largest battleships and France had built large numbers of them. Torpedo boat destroyers were small, fast warships equipped with the then novel water-tube boilers and quick-firing small calibre guns.
Fisher was knighted in 1894 and put in charge of the North Atlantic and West Indies station in 1897 before heading the British delegation to the First Hague Peace Convention. Following this he was made chief of the Mediterranean station from 1899 until 1902. Unlike the North Atlantic station, it was a vital British operational commands because of the line of communication between India and the UK which passed through the Suez Canal and which was felt to be under continuous threat from France.
In 1902 he returned to the UK as Second Sea Lord, in charge of personnel and in 1903 became commander in chief of Portsmouth dockyard. In October 1905 he was appointed First Sea Lord, the overall operational commander of the Navy.
By then France had become a close ally whilst Germany and Britain were embarking on a naval arms race. Fisher determined to build up a hugely powerful Home Fleet (renamed to Channel Fleet, the old Channel Fleet becoming the Atlantic Fleet) at the expense of overseas stations. Amidst massive public controversy, he ruthlessly sold off 90 obselete and small ships and put a further 64 into reserve, describing all these vessels as "too weak to fight and too slow to run away", and "a miser's hoard of useless junk". This freed up crews and money to increase the number of large modern ships in home waters.
He was a driving force behind the development of the fast, all big-gun battleship, and chairman of the Committee on Designs which produced the outline design for the prototype, HMS Dreadnought. His preferred model was a version where speed was substituted for armour, this became the battlecruiser, the first being HMS Invincible. He also encouraged the introduction of submarines into the Royal Navy, and the conversion from a largely coal fueled navy to an oil fueled one. He had a long-running and public feud with another admiral, Charles Beresford.
He was made a baron in 1909 (taking the motto "Fear God and dread nought" on the coat of arms as a reference to Dreadnought) just before his retirement in 1910. On the outbreak of the First World War he was recalled as First Sea Lord, after Prince Louis Battenberg had been forced to resign because of alleged German ties. Fisher resigned on May 15 1915 amidst bitter arguments with the First Lord of the Admiralty, Winston Churchill over Gallipoli, causing Churchill's resignation too. Fisher had opposed to the campaign from the outset, preferring an amphibious attack on the German Baltic Sea coastline, even having shallow draft battlecruisers such as HMS Furious and HMS Courageous constructed for it. As the Gallipoli campaign failed relations with Churchill had become increasingly acrimonious.
He was made chairman of the Government's Board of Invention and Research until the end of the war. He died of cancer in 1920.
Autobiography Memories and Records, Hodder and Stoughton, 1919
Biography Fisher's Face by Jan Morris