Marvin Milkes (August 10, 1923 – January 31, 1982) was an American front office executive in three professional sports: Major League Baseball, soccer, and hockey. He is perhaps best known as the first general manager in the history of baseball's Seattle Pilots and—when that franchise was transferred after its only season in the Pacific Northwest—Milwaukee Brewers.
Milkes' baseball career began in 1946 when he became an executive with minor league affiliates in the St. Louis Cardinals' vast farm system. He won The Sporting News' Minor League Executive of the Year Award (Lower Classification) in 1956 as general manager of the Fresno Cardinals of the Class C California League. Beginning in 1957, he was the GM of the San Antonio Missions, then the Double-A Texas League affiliate of the Baltimore Orioles. When the Orioles dropped the affiliation after the 1958 season, Milkes worked to keep the Missions franchise alive, securing a working agreement with the Chicago Cubs.
In 1961, he joined the front office of one of the American League's first expansion teams, the Los Angeles Angels. Serving as assistant general manager to Fred Haney, Milkes helped build the organization. One of his duties beginning in 1965 was to supervise its Triple-A club, the Seattle Angels of the Pacific Coast League, and when Seattle was granted an AL expansion team for 1969—the Pilots—Milkes was named its first general manager.