He was awarded the U.S. military's highest decoration, the Medal of Honor, for his actions as commander of navy forces at the Battle of Veracruz, Mexico.

He was also the uncle of Frank Jack Fletcher, another U.S. Navy admiral who also received the Medal of Honor for actions at Veracruz, and who commanded American naval forces at the battles of Coral Sea, Midway, in the Eastern Solomons, and the Aleutian Campaign during World War II.

Promoted to ensign in July 1876, he had sea duty on the sloops of war Portsmouth, Plymouth, Lackawanna and Constellation before participating in USS Ticonderoga's voyage around the world in 1878–1881.

Fletcher advanced to the rank of master (later lieutenant, junior grade) in April 1882 and was next assigned to the Hydrographic Office in Washington, D.C.

After a brief tour as Assistant Chief of the Bureau of Ordnance in the spring of 1898, Lieutenant Fletcher became commanding officer of the converted yacht USS Kanawha.

Fletcher attended the Naval War College courses in both 1907 and 1908 and in 1908 was assigned to the navy's General Board during the next year.

In April 1914, Fletcher led U.S. Navy forces during the landings at Vera Cruz, Mexico, receiving the Medal of Honor for his "distinguished conduct in battle".

[1] In September 1914, Fletcher began two years as the Atlantic Fleet's Commander in Chief, and was elevated to the rank of admiral in March 1915, the senior of the first three officers to hold the new four-star positions.