in 2015, mcmullin was a member of the b20 turkey 2015 taskforce on trade in istanbul, turkey. from 2014–2016 he was the director of australasian dispute resolution centre, which facilitates international mediation and cross-border dispute resolution in the asia pacific region. from 2013–2015 mcmullin held the position of senior international business advisor for the minister of foreign affairs, timor-leste.