Born in St Catharine’s, Ontario, McAvoy studied at the University of Guelph before completing her Bachelor of Fine Arts at the Nova Scotia College of Art and Design where she continues to teach part time. McAvoy studied printmaking and drawing but turned to painting shortly after graduating.

For many years Marilyn’s work was inspired by classical Dutch Flower painting and the cultivation of her own garden. A traditional approach to this subject matter changed dramatically in the early 1990’s after she began working on film productions. McAvoy began to incorporate the visual elements on discarded scenic staging with her classical flower imagery. Collage and juxtaposition remained key compositional strategies for her for many years.

After six months working on James Cameron’s Titanic, Mexico became a place of particular importance for Marilyn and she later lived a year there in the famed artist community of San Miguel de Allende. Mexican Arts and Crafts became a new inspiration for her paintings. In 1998 moved by her mother's death and with the help of a Canada Council Grant she returned to various regions of Mexico in order to observe El Dia de los Muertos. The work following this became highly influenced by tomb imagery and stencil designs. In the Viaje Series, she painted visual elements from above ground tombs on top of canvas prepared with projected details from her mother’s hand written recipes. Her Vanitias Series features paintings of flowers and shadows from graves alongside painted faux surfaces utilizing scenic paint techniques.

In recent years McAvoy’s work has turned to figure painting. The inspiration for this work initially was fuelled by song lyrics and her connection to having lived a life surrounded by live music and back stages. The individuals represented are women who wove in and out of her life during this time. The backdrop for these paintings reflects the atmosphere of this time and space. Marilyn’s visions are developed through a small stage setup in her studio. Here digital projections of photos from music hall concerts and back stages create the lighting. The addition of props and her models completes the scene, creating a filmic quality in this work.

Marilyn has been the recipient of Canada Council and Nova Scotia Arts Grants. A finalist in the 2003 RBC New Canadian Painting Competition, McAvoy has exhibited in galleries across Canada and the United States. The former competitive figure skater works on multiple canvases at once, always having a painting on the go that is technically demanding, another more playful and spontaneous. “It’s the figure skater in me,” says McAvoy: “freestyle and compulsory figures”.