 McCullum is married and he is father of 3 boys (born 2010, 2012 and 2014), and has moved up to Auckland to work part-time as a construction recruitment agent.McCullum made his first class debut for Otago in the 1999–2000 season.His first List A match came in the 2000–01 season and his first Twenty20 domestic match was against Canterbury at Christchurch on 13 January 2006.