In the 2011 Canadian General Election, Doré Lefebvre ran in her home riding of Alfred-Pellan, in eastern Laval, for the New Democratic Party (NDP).[2] She defeated incumbent Bloc Québécois candidate Robert Carrier by over 10,500 votes.[3]
Following her election, Doré Lefebvre's NDP colleagues voted her vice-chair of the federal caucus. She was also selected to chair the legislative committee, where she would be responsible for coordinating the NDP MPs' analysis of proposed laws. In April 2012, Doré Lefebvre was named by NDP leader Thomas Mulcair to the shadow cabinet as Deputy Critic for Public Safety.[4]
In her role as Deputy Critic for Public Safety, Doré Lefebvre has taken on important portfolios related to border security, Canada's network of penitentiaries and the treatment of women in the penal system. She has been sharply critical of the closing of the Leclerc Institution, within her riding, as well as the mistreatment of female prisoners and inadequate border security practices.[5]
Doré Lefebvre's work with citizens in Laval garnered national media attention in early 2013, when she fought the deportation of the Reyes-Mendes family, who resided in her riding.[6]
Doré Lefebvre was defeated in the 2015 election by Liberal candidate Angelo Iacono.