Lyle was born and raised near Pense, Saskatchewan, where he continues to farm and ranch on the Stewart family farm.

Mr. Stewart was one of the first members in the newly-formed Saskatchewan Party and was elected to the Legislative Assembly as the MLA for Thunder Creek in 1999. He was re-elected in 2003 and 2007. During his two terms in opposition, Mr. Stewart served as the Interim Leader of the Party, as well as the critic for Agriculture, Economic Development and Industry and Resources.

Mr. Stewart is a member of the Saskatchewan Stockgrowers Association and the Western Canadian Wheat Growers Association.

He and his wife Linda, have three grown children and one grandchild.

Lyle has established himself as an effective voice for rural Saskatchewan and wants to see it prosper.

Mr. Stewart is currently a member of the caucus' Standing Policy Committee on the Economy.