 Williams joined the Navy Reserve on May 22, 1942, went on active duty in 1943, and was commissioned a second lieutenant in the United States Marine Corps as a Naval Aviator on May 2, 1944.Williams also played on the baseball team in Chapel Hill, North Carolina, along with his Red Sox teammate Johnny Pesky in pre-flight training, after eight weeks in Amherst, Massachusetts, and the Civilian Pilot Training Course.While on the baseball team, Williams was sent back to Fenway Park on July 12, 1943, to play on an All-Star team managed by Babe Ruth.