Lagacé Dowson is married to Brian McKenna, an independent television documentary film maker.
She has been selected as the New Democratic Party candidate in the upcoming by-election in Westmount—Ville-Marie, and is currently on extended leave without pay from CBC Radio.
On August 18, she was endorsed by Cory Doctorow of Boing Boing. She was also endorsed by McGill University academics Charles Taylor and Desmond Morton, human rights lawyer Julius Grey and the former mayor of Westmount, May Cutler.
She is the daughter of Hugh Dowson and Claire Lagacé and the niece of Ross Dowson.