 Johnson graduated with Bachelor of Science degree on June 6, 1929 and was commissioned Ensign on that date.He also married the former Margaret Louise Gross (November 26, 1910 – July 4, 1998), on the same day.His first assignment as a junior officer was aboard the battleship USS "Tennessee" and remained with that ship until May 1930, when he was transferred to the battleship USS "West Virginia" for duty on the staff of Commander Battleship Divisions, Battle Fleet under Admiral Frank H. Schofield.