Born in Brooklyn, New York, MacPhee attended Erasmus Hall High School, where he was class president, played football, and was captain of the baseball and ice hockey teams.

[1] Upon graduating from Princeton in 1922, MacPhee was signed by the New York Giants and Baseball Hall of Fame manager John McGraw.

MacPhee recorded a hit and a walk in four plate appearances against Phillies pitcher Jimmy Ring, and scored the tying run in the Giants' 3–2 victory.

[2] His second and final appearance came three days later in another back end of a doubleheader at the Polo Grounds, this time against the Boston Braves and hurler Garland Braxton.

[8][9] A multi-sport professional athlete, MacPhee played in 10 games as a running back for the NFL's Providence Steam Rollers during their 1926 season under head coach Jim Laird.