Rebelo rose to prominence in the 1986 season by winning the Paris Marathon in the time of 2:32:16. Winner of her first national marathon title in 1990, Maria Rebelo took third at the 1990 European Championships at Split, finishing behind the Portuguese Rosa Mota and the Soviet Valentina Yegorova. She ran the best performance of her career on 21 April 1991 by completing the London Marathon in 2:29:04, then she placed fifth at the 1991 World Championships at Tokyo in 2:32:05. Selected to run at the 1992 Olympic Games, Rebelo did not finish. She won two more in 1993 and 1994.