Fred Cobain was elected as a Belfast City Councillor in 1985, representing the Ulster Unionist Party. He served on Council until 2001, acting as Lord Mayor in 1990.

Cobain was elected as a member of the Northern Ireland Assembly in 1998. He chaired the Assembly's Committee for Social Development and served two terms on the Northern Ireland Policing Board. Cobain was re-elected as an MLA in 2003 and 2007.

Cobain is a trade union activist. He works with the Simon Community and the Northern Ireland Council for the Homeless.

In 2007, Cobain was awarded an MBE. He left the Ulster Unionist Party in 2013 and joined the Democratic Unionist Party.