Stephen is a local - he lives in Largs Bay with his wife Antonia and sons Benjamin and Isaac, where his father and his family are from. He spent much of his childhood at Alberton Oval watching the Magpies, at the beach at Largs, or fishing off North Haven. When it came time to buy his home, he only wanted to live in Largs.
Mr Mullighan was first elected as the Member for Lee in the South Australian Parliament in 2014.
Mr Mullighan took up his position as Minister for Transport & Infrastructure, Minister Assisting the Minister for Planning, Minister Assisting the Minister for Housing and Urban Development on 26 March 2014.
In 2016, Mr Mullighan was appointed the Minister for Housing and Urban Development.
Prior to his appointment as Minister, Mr Mullighan led Deloitte's economics team in Adelaide between 2010-2013, providing economic advice to corporate clients, non-profit sector and state and federal governments.
He served as the Deputy Chief of Staff to the South Australian Premier and Treasurer, Hon Jay Weatherill MP, from 2013 to 2014. During this time Mr Mullighan was responsible for several key policy areas including budget development, taxation policy, investment strategy and State-Commonwealth financial relations.
He holds a Bachelor of Arts degree from the University of Adelaide.
Mr Mullighan was returned as the Member for Lee at the 2018 South Australian Election.