McCullum is married; he is the father of three boys (born 2010, 2012, and 2014), and he has moved up to Auckland to work part-time as a construction recruitment agent. He became the general manager of Total Property Vorx, which is a construction firm in Auckland. He was also invited by the New Zealand consulate in Dubai to promote the country's pavilion for Expo 2020. Nathan specialised in the field of industrial and commercial construction, including land building maintenance and office refurbishment.
