Having received his commission, Jackson served as assistant inspector of ordnance and then inspector of ordnance at the
Midvale Steel Works, then drew sea duty aboard the torpedo boat
Cushing and monitor
Puritan. In 1897, he married the daughter of Rear Admiral
William T. Sampson, who would achieve fame a year later at the
Battle of Santiago Bay. He won the annual essay contest administered by the
United States Naval Institute in 1900. He served aboard the torpedo boat
Foote during the
Spanish–American War,{{citation In 1910 he sailed to the Far East for shore duty at
Naval Station Cavite. In 1911 he went to sea as commanding officer of the protected cruiser , then as commanding officer of the gunboat
Helena, in which role he also served as senior officer in command of the gunboats of the
Yangtze River Patrol during the
1911 Revolution. He returned to the United States in 1912 for another tour at the Naval Academy, followed by duty with the General Board from 1913 to 1915 and command of the battleship
Virginia in 1915. In June 1917, following the United States entry into
World War I, he was dispatched to Paris as special representative from the
Navy Department to the French Ministry of Marine, then served as naval attaché in Paris until after the
Armistice in November 1918, when he returned to the United States to report to the
Office of Naval Intelligence. In 1919, as senior officer for the U.S. Naval Forces in
Bermuda, he commanded the
Azores detachment of the
Atlantic Fleet that stood guard for the Navy flying boat
NC-4 on its historic first trans-Atlantic crossing by an aircraft. ==Flag officer==