Joseph John Mack (né Maciarz, January 4, 1912 – December 19, 1998) was an American Major League Baseball first baseman who played for the Boston Braves in 1945.

Mack is one of many ballplayers who only appeared in the major leagues during World War II.

He made his major league debut on April 17, 1945 (Opening Day) against the New York Giants at Braves Field.

He was Boston's regular first baseman until the July 4, when he played in his last big league game.

This biographical article relating to an American baseball first baseman is a stub.