He received a Master of Science degree in aeronautical systems from the University of West Florida while earning his naval aviator wings in 1975.

[3] He served in Attack Squadron 15 aboard USS America, flying the A-7E Corsair with Adm Mark P. Fitzgerald.

Johnston next studied at the Naval Postgraduate School, Monterey, where he received a Master of Science degree in aeronautical engineering (avionics).

[4] While serving as head of the Naval Air Warfare Center Weapons Division, he was promoted in early March 2000.

[5] His further promotion to Rear Admiral (Upper Half) was submitted to the Senate for approval in May 2001[6] and authorized in April 2002.