Brenner served with the Army Air Force as a B-17 pilot and flew 29 missions over Europe as a squadron group leader. “I was just as scared on my last mission as I was on the first,” he told The Sporting News on August 2, 1945. “I had a mighty fine crew. We were lucky, too. We had four planes shot up, but none of us got more than minor scratches and we always managed to land back at our base.”

Brenner describes his toughest mission: “We were on a bomb run over Brux, Czechoslovakia. We were up for nine and a half hours. We lost a lot of planes and crews that day, but we were lucky. Got back okay, but our plane looked like a sieve and had to be junked. Some of us were so badly shaken up mentally the flight surgeons wanted to send us to a flak home for a rest, but we out-talked ‘em.”

Then he recalled: “Of course, going over Berlin was always rugged – always plenty of flak and fighter opposition.”

Captain Brenner was awarded the Distinguished Flying Cross with two Oak Leaf clusters and the Air Medal with three clusters. He was honorably discharged in July 1945 and returned to baseball to play with Los Angeles, appearing in 22 games before the end of the season and batting .234.

Brenner remained in baseball as a player-manager until the late 1950s with such teams as Vancouver, Yakima, Lewiston, Seattle and Portland. He also turned his hand to pitching late in his career and enjoyed three successive 20-win seasons between 1952 and 1954 with Lewiston and Vancouver of the Western International League.