As a young man he helped run family ranching and dairy businesses in Chickasha.

While attending the Missouri Military Academy, he enlisted in the Oklahoma National Guard at age 16.

Larson was a member of the National Guard, and he was called into service as an artillery officer in the Army during World War II.

He served in Italy and received the Legion of Merit and the Purple Heart medals.

In 1946, Jess Larson was appointed general counsel of the War Assets Administration, which was charged with disposing of surplus defense property.

For this work the Air Force conferred on him its Exceptional Civilian Service Award.