Cleveland selected McCullough at the age of 43, choosing him as the 22nd pick in the 2002 draft from Eastern Carolina. He spent the years 2002 to 2005 playing in their minor league system and even briefly made an appearance in Triple-Buffalo in 2005. Following this, McCullough ventured into a managerial role within Toronto's minor league system from 2007 to 2014. Subsequently, the Dodgers brought him on board as their minor league field coordinator. In 2021, he received the nod to join the Dodgers' major league coaching staff, and he recently wrapped up his second year as their first base coach. During his tenure in Toronto's minor league system, McCullough compiled an impressive record of 402 wins and 367 losses. Additionally, he has previously interviewed for managerial positions with the Mets and the Royals.