After graduating from high school in Whitehall, Montana in 1933, Pomerleau joined the Marines and served in China from 1934 to 1937. He was discharged honorably from the Marines as a sergeant in 1938. After his discharge, Pomerleau worked for a construction company in Nevada, and then for the U. S. Border Patrol in California and Arizona. In 1942, after World War II began, he re-enlisted and served in the Military Police Corps of the United States Army. Pomerleau served in the Guadalcanal Campaign, the Battle of Tarawa, the Battle of Saipan, and Battle of Tinian. Pomerleau was discharged in 1945.