She was elected to the seat in 2002 following the retirement of long-term member Brian Stephens. She is a member of the Liberal Democratic Party of the United Islands; she was elected as a member of the United Islands Liberal Party. In 2005 she was re-elected by an increased margin.
In the minor reshuffle on November 26, 2006, Houston was promoted directly into the ministry as Minister for External Territories and Local Government. At 37, she was the youngest member of the federal ministry. Ten days after her appointment, Houston issued a white paper concerning the possible future of the island of Corbana - Houston was said to personally favour selling the island.
The Liberal Democrats lost office in 2007. Houston supported Lawrence Porter's leadership bid. In the new Shadow Cabinet of new leader Robin Sales, Houston was named as Shadow Attorney General.
Houston is a member of the party's broad left grouping.