Gregory Jamieson Clark is a Canadian politician from Alberta. He is the former leader of the Alberta Party, and in the 2015 Alberta general election was elected the party's sole Member of the Legislative Assembly, representing Calgary-Elbow. Clark resigned as leader on November 18, 2017, and served as interim leader until the leadership election when Stephen Mandel was elected the new leader of the party.

Stephen Mandel is a Canadian politician and leader of the Alberta Party from 2018 to 2019. He previously served as an Alberta cabinet minister from 2014 to 2015 and as mayor of Edmonton, Alberta for three terms from 2004 to 2013. Prior to being mayor, he was a councillor for three years.