Cathie was born in Stirling in 1954. She grew up with her four sisters in Kilsyth and attended Kilsyth Academy

Cathie is a member of the Scottish Labour Party, which she joined in her teens. She used to be a Cumbernauld and Kilsyth District Councillor from 1984 to 1994, becoming Council Leader between 1994 and 1996. She was then a North Lanarkshire Councillor from 1996 to 1999.

Cathie was elected to be the first Member of the Scottish Parliament for Cumbernauld and Kilsyth in 1999, and was successfully re-elected in 2003 and 2007.

In The Scottish Parliament Cathie serves on the powerful Justice Committee and is Vice-Convenor of the Standards, Procedures and Public Appointments Committee. She also convenes the Cross Party Groups on Deafness and Housing. Cathie's Political interests include health, housing, disability rights, equalities and social inclusion.

Cathie is a member of the trade union Unite: Amicus. She is also a trustee of the Scottish Mining Convalescent Trust and an Ambassador for Deaf Parents UK. In her leisure time Cathie likes reading, cycling and family holidays.