He was promoted to team president, a position that had been vacant for about a year after the death of the previous team president Stephen McKeever, on May 4, 1939. In 1939, he received the Sporting News Executive of the Year Award.
MacPhail was pivotal in the development of pioneering sportscaster Red Barber, who announced Reds and Dodgers games for MacPhail. MacPhail’s innovations include nighttime baseball, regular game televising, and flying teams between cities. MacPhail resigned as president of the Dodgers on September 23, 1942, to accept a commission in the United States Army. By the end of World War II, MacPhail held the rank of colonel.