Mackanin spent nine seasons playing in the majors, breaking in with the Texas Rangers in 1973 and finishing with the Minnesota Twins in 1981. In between, he spent time with the Philadelphia Phillies and Montreal Expos. He was Montreal’s starting second baseman in 1975 and 1976. He had his best year at the plate in 1975, hitting .225 with 12 home runs, 11 stolen bases, 59 runs scored and 44 RBIs. In 548 games Mackanin hit .226 with 30 home runs.
Mackanin went on to work as a scout, coach and manager in the majors after his playing days concluded. He served as the manager for the Phillies from 2015-2017 and was the interim manager for the Pittsburgh Pirates in 2005 and Cincinnati Reds in 2007.