After his playing career, Marshall managed the Chicago Cubs (1974–76) and the Oakland Athletics (1979) but never enjoyed a winning season in either post.

Born in Danville, Illinois, and raised in Long Beach, California, he threw and batted left-handed and was listed as 6 feet 1 inch (185 cm) tall and 190 pounds (86 kg; 13 st 8 lb).

He was part of the first interleague trade (without waivers) in baseball history when he was dealt by the Cubs with pitcher Dave Hillman to the Boston Red Sox for first baseman Dick Gernert on November 21, 1959.

He never appeared in an official game for the Red Sox, who traded him (in a waiver deal) to the Giants for pitcher Al Worthington during spring training in 1960.

Marshall concluded his managerial career in minor league baseball during the 1980s, working for the New York Yankees (1984) and Chicago White Sox (1986).