Grünewald made her career break in 1935 with the role of Esther, originally played by Elsa Fouché, in Oom Paul, presented by Hendrik and Mathilde Hanekom's touring company.

She stayed with the Hanekoms for a number of years before joining André Huguenet for Die Kwaksalwer in 1939.

She played opposite Huguenet as Ophelia in his Afrikaans-language version of Hamlet in 1947 and as Lady Macduff in Macbeth in 1950.

[1] She also appeared in a small number of films: uncredited, in Zoltan Korda's film version of Cry, the Beloved Country (1951), Bladon Peake's Inspan (1953) and Gerrie Snyman's Die Leeu van Punda Maria (1954).

She then married American playwright Robert Ardrey on 11 August 1960.