During his time in government he has served in several Parliamentary Assistant roles assisting ministers including the Minister of Northern Development and Mines (2003–2007, 2011–2013) and the Minister of Natural Resources (2007–2009). On March 25, 2014, Premier Kathleen Wynne appointed Mauro as Minister of Municipal Affairs and Housing. On June 24 after the election she appointed Mauro as the Minister of Natural Resources and Forestry. After fellow cabinet minister Michael Gravelle temporarily stepped aside in February 2017, Mauro also took over his duties as Ministry of Northern Development and Mines on a temporary basis.