Nilsson was born in Stockholm, and trained there at the drama school of the Royal Dramatic Theatre.

She appeared in three Ingmar Bergman films: Till Glädje (To Joy, 1950), Sommarlek (Summer Interlude or Illicit Interlude, 1951), and Kvinnors Väntan (Secrets of Women or Waiting Women, 1952).

She also appeared in the English-language film A Matter of Morals (1961), directed in Sweden by John Cromwell.

[1] Maj-Britt Nilsson died in Cannes, France, aged 82.

Her death, which was not widely reported outside Sweden, was confirmed by Jon Asp, executive editor of the online publication Ingmar Bergman Face to Face.