She debuted at Nationalteatret (the National Theatre) in 1981, and has worked there since. Here she has had roles such as "Polly" in Brecht"s The Threepenny Opera, and "Mistress Sørby" in Ibsen"s The Wild Duck.
She has also acted in outdoor performances of Ibsen"s Peer Gynt, and in several one-woman shows.
In film and television she is best known for her roles in Drømmeslottet (1986) and "Pilen flyttebyrå" (television, 1987). Maurstad took part in the reality show "Skal vi danse" (based on "Strictly Come Dancing") in 2007.
Mari Maurstad"s father was the renowned Norwegian actor Alfred Maurstad, and actor Toralv Maurstad is her half-brother.