After one season as a volunteer assistant coach for East Carolina,[2] McCullough served as a manager in Minor League Baseball for the Toronto Blue Jays organization from 2007 to 2014, working in the Rookie and Single–A levels and compiling a record of 629–559.[3] before being hired by the Los Angeles Dodgers as their Minor League Field Coordinator. The Dodgers named McCullough their major league first base coach prior to the 2021 season.[3]
On November 11, 2024, McCullough was named the manager of the Miami Marlins.[4]