Wallace's first solo exhibition in 1955 evoked critical praise and moved her to the front ranks of South African art, a position she retained to the end of her life. Among other distinctions she was awarded prizes at the Quadrennial Exhibitions in 1960 and 1964, and another at the 1981 Republic Festival exhibition. Today, her works are included in numerous public and private collections.
During her lifetime she held many exhibitions in Paris and South Africa , co-founded the Cape salon, served on the central committee of the South African Association of Arts and was a founder member of the Artists' Gallery and the Artists' Guild in Cape Town . Wallace went to great lengths to advise black and coloured artists and to promote their work; and one of those she tutored, the Langa painter Grace Mgudlandu, was honoured with a retrospective exhibition at the South African National Art Museum in 2004.