Primarily a painter, Johnson's work dealt with dreams and imagination, providing enough detail to recognize figures and spaces but "encourages us to contemplate endings, meanings and loss.

[10] With a feminist outlook, and using domestic interiors and natural landscapes as starting points for her paintings,[11] her works have been noted for their diary-like quality, being "like notations in a journal," of simple memories.

[14] Johnson showed extensively throughout Toronto and Canada, including yearly solo exhibitions at the Carmen Lamanna Gallery from 1983 to 1991.

She was represented by Christopher Cutts Gallery in Toronto,[15] which is where she held her last exhibition before her death, entitled Angels and Monsters.

In 2017, she was selected to be the visual editor of the Theatre Passe Muraille 50th anniversary book, and was recently included in A Concise History of Canadian Painting third edition.