Lessig first served with the US Navy as an airplane mechanic before transferring to the USAAF in 1935. He served as a pilot with the 20th Pursuit Squadron.

When the Eighth Air Force was established in the UK in 1942, Lessig was assigned to 8th Air Force Bomber Command as an operations and training officer, he later served as a liaison to the British Air Ministry and was appointed to the Combined Operations Planning committee as a representative of the 8th Air Force.

On 25 March 1942, after training at the RAF Staff college, Lessig became the first 8th Air Force pilot to fly a combat mission, when he accompanied the RAF on a fighter sweep over France. He then went on to fly one mission with the Royal Air Force bomber command and six combat missions with the Eighth Air Force accumulating 38 total combat hours in a Spitfire, a Lancaster, B-17s and B-26s in the European Theatre.

Lessig returned to the US in 1944, where he assumed duties as deputy chief, Theaters, Commitments and Implementation Branch, Army Air Force Headquarters, Washington, D.C. His later career saw him act as a commander in Japan, Korea and with NORAD (North American Air Defense).

Awards: LOM, BSM, AM, WWII Victory, EAME.