From 2000 to 2002, Dompnier took professional training as an actor in the Ateliers du Sapajou in Paris, Marie furthered her education in 2003, at the Centre Dramatique National in Poitiers. From 2002 to 2004, she also studied at the Conservatoire National Superieur d'Art Dramatique, 5th arrondissement of Paris. Dompnier joined the L’École régionale d’acteurs de Cannes in 2004, graduating in 2007.

Dompnier spent most of her early acting career performing in classical and contemporary works in the theatre. Dompnier was part of the company Artéria in residence at the Théâtre du Soleil until 2004. Then Marie joined the collective "La Vie brief", with whom she played Robert Plankett in 2011, in a staging of Jeanne Candel In 2014, Dompnier was part of the taste of fake and other songs, in Jeanne Candel. In 2012, she appeared for the first time in the cinema in Dante Desarthe's Je fais feu de tout bois, before securing a small role in the television series Caïn in 2012 and Détectives in 2013.

In 2014, she played the role of Charlotte Poussin in the film Les Gazelles alongside myriad actresses including Camille Chamoux, also co-writer. She befriended the latter and staged her show, born under Giscard.

Festival International des programmes audiovisuales de Biarritz 2015: FIPA d'or for female interpretation in a television series for the Witnesses