Government House Leader is not technically a cabinet-level post, but rather a parliamentary office, so in order to qualify for cabinet membership the individual must be named to cabinet in some other capacity. In recent years, with the position evolved into a full-time job, House Leaders have been named to cabinet as Ministers of State with no portfolio specified. The Martin government has taken to styling these positions so that the Minister of State title is effectively invisible.
1. The Turner Ministry never convened the House, so Ouellet never technically served as Government House Leader. He was also named "Minister of State for Economic and Regional Development".
4. The Campbell Ministry never convened the House, so Lewis never technically served as Government House Leader