Maria was a pioneering actress in addressing issues of sexuality, purchasing the Portuguese rights to The Vagina Monologues by Eve Ensler, and performing the show to popular acclaim in the Lisbon area of Portugal.
[1][2][3] Sergeant started her television acting career in 1979, at the age of 9, in a series of 12 episodes called Histórias com Pés e Cabeça (Head and foot stories).
In 1988, she played her first big role, as Rosarinho in the soap opera Passerelle, written by Rosa Lobato de Faria and Ana Zanatti.
In 1992 and 1993, she participated in the soap opera Cinzas on the state broadcaster RTP and also appeared in films, including Aqui d'El Rei directed by António-Pedro Vasconcelos.
Further soap operas followed and she also appeared on television performing an erotic dance with the architect of Portugal's Carnation Revolution, Otelo Saraiva de Carvalho.