He taught school for a year in La Due, Missouri, before enlisting in the United States Army Air Forces in July 1941.

[1] When Jerstad heard of the upcoming low-level bombing mission against the oil refineries at Ploieşti, Romania, he volunteered to lead a formation.

[3] Three miles from the target, Jerstad's bomber, nicknamed "Hell's Wench", was badly damaged and set aflame by enemy ground fire.

On 1 August 1943, he served as pilot of the lead aircraft in his group in a daring low-level attack against enemy oil refineries and installations at Ploesti, Romania.

Although he had completed more than his share of missions and was no longer connected with this group, so high was his conception of duty that he volunteered to lead the formation in the correct belief that his participation would contribute materially to success in this attack.

Maj. Jerstad led the formation into attack with full realization of the extreme hazards involved and despite withering fire from heavy and light antiaircraft guns.

By his voluntary acceptance of a mission he knew was extremely hazardous, and his assumption of an intrepid course of action at the risk of life over and above the call of duty, Maj. Jerstad set an example of heroism which will be an inspiration to the U.S. Armed Forces.

The Legacy Museum, run by the Racine Veterans Center, includes an exhibit of photographs and artifacts relating to the two men.