Soon after, both Alexandra and her twin sister Isobel began nurse's training at Columbia Hospital for Women in Washington, D.C. After her graduation, Luke returned to Oshawa and married Marcus Everett Smith.

Luke painted landscapes in a large, third floor studio in her and her husband's home and soon discovered abstract art after visiting modernist exhibitions in Toronto and Ottawa.

From Hofmann's teachings, she began to understand how to create energy in her paintings with colour, texture and the use of white space as well as formal structure.

[6]In 1980, her work Symphony (1957) (Robert McLaughlin Gallery) in the Painters Eleven in Retrospect exhibition was praised as "the surprise of the exhibition", demonstrating many of the virtues of Painters Eleven at their best: "their ambition to make painting more autonomous, like music; their marvellous freedom and fluidity of touch; their modest directness in relation to the subject; their freedom to move anywhere their inspiration took them".

[3] Shortly before her death, Luke and her husband Ewart offered major financial support and works from their own collection toward the creation of a public art gallery for the City of Oshawa.