Allan MacMaster was first elected to the Nova Scotia House of Assembly as MLA for Inverness in a by-election in 2009 and was re-elected in 2013, 2017, and 2021.

He sits on the Treasury and Policy Board.

He has been Deputy Premier, Minister of Finance and Treasury Board, Minister of Communities Culture, Tourism and Heritage, Minister of Labour Relations, Minister of Gaelic Affairs, Minister responsible for the Voluntary Sector, and Opposition House Leader.