The daughter of engineer Luiz Eduardo Osório Negrini, and pedagogue Neusa Vidal de Negreiros, who is descended from André Vidal de Negreiros, Alessandra, who has Portuguese and Italian ancestry, has a brother named Paulo Roberto,[1] who spent his childhood and adolescence in Santos.

[3] In 2000, she began playing Isabel Olinto in the critically acclaimed miniseries A Muralha, a tribute to 500 years in Brazil.

[3] Because of the sensual appeal of her character in the miniseries, she was featured on the cover of the Brazilian edition of Playboy magazine in April of that year.

[4] In 2002, Negrini received accolades for voicing the villain Selma in a recording of the novel Desejos de Mulher by Euclydes Marinho.

[9] The same year she premiered the film Cleópatra, Júlio Bressane, for which she won the best actress award at the Festival de Brasília.

In 2008, she appeared in two more films: A Erva do Rato, of Júlio Bressane and No Retrovisor of Mauro Mendonça Filho.

[17][18] In 2014, Alessandra played Susana in Boogie Oogie, the novel by Rui Vilhena, replacing Meu Pedacinho de Chão.