After his playing days ended, Aker managed in the minor leagues in 1975–85, winning the Governor's Cup (International League Championship) with the 1982 Tidewater Tides (Mets organization), and was the Cleveland Indians pitching coach from late 1985 to 1987.
After retiring from playing, Aker continued in minor league baseball from 1975 to 1985, winning the Governor's Cup (International League Championship) with the Tidewater Tides for the Mets organization. He later served as the Cleveland Indians pitching coach from late 1985 to 1987.