Born July 3, 1965 in Shediac, New Brunswick, Marie-Jo Thério grew up in Moncton, where she learned the piano very early. At 16, she put on her first show in her hometown, then left l’Acadie for Montreal a year later to study literature and theater.
Noticed by the author Michel Tremblay, she obtained the role of Gertrude, the sister of Émile Nelligan, in the romantic opera dedicated to the poet, which he prepared with André Gagnon. The show received the show of the year award at the ADISQ gala.
Subsequently, Marie-Jo played the role of Laura in the very popular television series Chambres en ville and also played in a few musical comedies, including Les Misérables and Notre-Dame de Paris.
In 1995, she recorded her first album, Comme de la musique, followed by a show and a tour. In 1997, she met Georges Moustaki at the Festival d'été de Québec, who invited her to open for him at the Casino de Paris.
In 1999, she starred in the morality drama Full Blast by Acadian filmmaker Rodrigue Jean. Her performance earned her the Jutra for best supporting actress.
In 2000, in her “cabane de Verchères”, she recorded the album La Maline with Bernard Falaise and Erik West Millet. This second album was praised by the public and critics and was followed by a tour. In 2001, she met Olivier Bloch-Lainé and this meeting resulted in the album Les Matins habitables.
The double album Chasing Lydie, a true "sonic road movie", released in April 2011, follows in the footsteps of a singing great-aunt who immigrated to the United States in the 1920s.
The live album Trois petits tours d'automne, recorded over three evenings, with three different improvising musicians each evening, was released in autumn 2014.
In 2020, she released a reissue of La Maline and a live recording of the show Un trois août au Spectrum de Montréal.
In 2023 and 2024, Marie-Jo Thério returned to the stage with the show La Maline, 20 ans et peu lunes.