Carleen Thomas is from the Tsleil-Waututh Nation in North Vancouver. She worked in education as a teacher and later as Manager of Education for the Tsleil-Waututh Nation. Additionally, as part of the Tsleil-Waututh Nation's Cheif & Council she was actively involved in community development including health and education. Carleen also represented her nation on the Nautsamawt Tribal Council.

In 2015, she ran as the New Democratic Party candidate for the North Vancouver general elections. She was nomited as the NDP candiate because of the work that she did for the Tsleil-Waututh Nation’s Sacred Trust Initiative, an initiative that was set up to oppose the Kinder Morgan pipeline expansion project in Burrard Inlet.