Scullion was a professional fisherman prior to entering politics. He was first elected to the Senate at the 2001 federal election, and briefly served as Minister for Community Services in the Howard Government in 2007. He was deputy leader of the National Party from 2007 to 2013, the first senator to hold the position, and served two terms as the party's Senate leader (2007–2008 and 2013–2019). In 2013, Scullion was appointed Minister for Indigenous Affairs in the Abbott Government. He held the same position in the Turnbull and Morrison Governments before retiring from parliament at the 2019 election.