He served as a member of the Legislative Assembly of Alberta from 1920 to 1926 sitting with the Liberal caucus in government and opposition.
Mills ran for a seat to the Alberta Legislature in a by-election held in the Athabasca electoral district on June 3, 1920.
Mills was projected to be returned unopposed,[2] however Conservative candidate John Angelo filed nomination papers at the last minute.
[3] The run up to the 1926 Alberta general election saw tension increase between Mills and the Liberal party.
Mills instead ran for re-election as an Independent Liberal and was defeated finishing last in a hotly contested race that went to ballot transfers.