Maxwell graduated from the Royal Academy of Dramatic Art in England and began her film career in the late 1940s, winning the inaugural Golden Globe Award for Most Promising Newcomer – Actress for her performance in That Hagen Girl (1947).

During World War II she ran away from home, aged 15,[2] to join the Canadian Women's Army Corps, a unit formed to release men for combat duties.

To avoid her being repatriated to Canada, she was discharged; she subsequently enrolled at the Royal Academy of Dramatic Art,[2] where she became friends with fellow student Roger Moore.

[4] Moving to Hollywood at the age of 20, Maxwell won the actress Golden Globe Award for Most Promising Newcomer for her role in the Shirley Temple-Ronald Reagan drama That Hagen Girl (1947).

[5] In 1949, she participated in a later famous Life magazine photo layout, in which she posed with other up-and-coming actresses, Marilyn Monroe, Cathy Downs, Suzanne Dalbert, Enrica Soma, Laurette Luez and Jane Nigh.

[3] One of her Italian films was an adaptation of the opera Aida (1953), in which Maxwell played a leading role, lip-synching to another woman's vocals and appearing in several scenes with the then unknown Sophia Loren.

Director Terence Young, who had turned her down on the grounds that she "looked like she smelled of soap", offered her either Miss Moneypenny or Bond's girlfriend, Sylvia Trench, but Maxwell was uncomfortable with the idea of a revealing scene outlined in the screenplay.

However, the producers felt it important to incorporate the regular character, and it was ultimately decided during production to add the scene where, disguised as a customs officer, she gives Bond his travel documents at the Port of Dover.

She reprised her character, weeping for the death of Bond, in a short scene with Bernard Lee in the French comedy Bons baisers de Hong Kong (1975).

During the filming of A View to a Kill (1985), her final appearance as Moneypenny, producer Albert R. Broccoli pointed out to her that they were the only cast or crew members from Dr. No who had not yet left the series.

She spent her summers at a cottage outside Espanola, Ontario, where she wrote a weekly column for the Toronto Sun under the pseudonym "Miss Moneypenny" from 1979 until 1994,[6] and became a businesswoman working in the textile industry.

She was always fun and she was wonderful to be with and was absolutely perfect casting [...] It was a great pity that, after I moved out of Bond, they didn't take her on to continue in the Timothy Dalton films.