Maxwell began studying for the stage around the age of 13. She joined John Clark for 2 years as the child co-host of his Junior Magazine series for CBC Television. She first performed at the Stratford Shakespeare Festival in 1956.
She first traveled to New York at age 19 in 1960. She debuted on Broadway in The Prime of Miss Jean Brodie in 1968, going on to five more plays with the Tyrone Guthrie Theatre in Minneapolis, Minnesota. In 1974, she was back on Broadway playing the role of Jill in Equus, which starred Anthony Hopkins.
She played Lavinia Mannion in the 1978 PBS adaption of Mourning Becomes Electra. In 2009-10 she appeared in two episodes of the Syfy series Warehouse 13.
In 1982, she starred as Rosalind in the Stratford Festival's stage production of Shakespeare's As You Like It, a production which was videotaped and telecast on Canadian television in 1983. In 2011, she played the Duchess of York in Richard III.
