 Brien was elected in the Témiscamingue electoral district under the Bloc Québécois party in the 1993, 1997 and 2000 elections, serving in the 35th, 36th and 37th Canadian Parliaments respectively.He had served as the party's whip from 15 August 2001 until 16 December 2002.Brien left the Bloc Québécois following his decision to seek a seat in the Quebec National Assembly with the Action démocratique du Québec (ADQ).