He is a Liberal member of the Western Australian Legislative Council, having represented South West Region since 2017.
He was previously a member of the Western Australian Legislative Assembly from 2005 to 2008 representing the electorate of Capel.
[citation needed] On entering Parliament Thomas was appointed as acting speaker of the Legislative Assembly (lower house) in March 2005 and was a member of the Public Accounts Committee from April 2005.
Thomas contested the seat in the 2008 election and lost narrowly to Labor candidate and member for Collie-Wellington, Mick Murray.
[4] He resigned from this role on 27 February 2024 after The West Australian newspaper revealed he had been in contact with former premier Brian Burke, despite Liberal leader Libby Mettam having claimed none of her frontbenchers had been in contact with Burke.