He fought in the Spanish–American War, played a prominent role in the independence of Panama from Colombia in 1903, and served as Commander-in-Chief of the United States Asiatic Fleet.

[2] Hubbard served aboard the sloop-of-war USS Brooklyn on the European Station from 1871 to 1874,[3] being promoted to ensign on 13 July 1871 and to master on 15 September 1873.

[3] After duty at the Naval Torpedo Station in Newport, Rhode Island, in 1883, Hubbard served at the Bureau of Navigation in Washington, D.C., from 1883 to 1884.

[3] On the eve of the Spanish–American War, Hubbard left Essex and reported aboard the auxiliary cruiser USS Yankee, then fitting out at New York City, in March 1898.

[3] Yankee was commissioned on 14 April 1898, and during the Spanish–American War participated in the blockade of Cuba, the Battle of Guantánamo Bay, and actions off Casilda and Cienfuegos.

He commanded Minnesota during her duties related to the Jamestown Exposition in Norfolk, Virginia, from 22 April 1907 to 3 September 1907 and during her voyage around the world as part of the "Great White Fleet" between 16 December 1907 and 22 February 1909.