Thomas Howard was born in Galena, Illinois on August 10, 1854 and was educated in the public schools. In 1868, through President Ulysses S. Grant, who spent the summer of that year in Galena, he was appointed to the US Naval Academy.  Howard graduated at the top of his class in 1873 and was promoted to ensign in 1874. In 1885 he made Lieutenant and in 1899 he made Lieutenant Commander, a very short period compared to the stagnation that other officers during the past 10 years had experienced.  During his career he served under George Dewey at the Battle of Manila Bay and successively commanded Chesapeake, Nevada, Olympia, Tennessee, and Ohio.   During 1908 he commanded the USS Ohio on the second leg of the cruise around the world from San Francisco to Hampton Roads.

In January 1914, Howard was appointed commander in chief of the U.S. Pacific Fleet. The same year, during the Mexican Revolution, Howard commanded a squadron of American vessels in the Gulf of California. Their mission was to observe the Topolobampo naval campaign. Three of Howard's warships were present at the Fourth Battle of Topolobampo. When the Marines established camp for the second time on San Diego's North Island, they named it Camp Howard, in his honor. In 1915, he became the fifth full admiral in the history of the U.S. Navy when the three commanders in chief of the Atlantic, Pacific, and Asiatic Fleets were each advanced to the temporary rank of full admiral. Upon relinquishing command of the Pacific Fleet in September 1915, Howard reverted to his permanent rank of rear admiral.