He played a key role in resettling Doukhobor religious dissidents from the Russian Empire to Canada.

[1] In 1892, upon the recommendation of University of Toronto Professor William Ashley who was leaving for Harvard University, he took Ashley's chair of Political Economy and Constitutional History, moving to Toronto with his family (including daughter Dora who would later become a major figure in Canada's theatre).

In 1893, James Mavor was a founding member of the Toronto Chapter of the Alpha Delta Phi Literary Society.

Through several years that followed, he took a keen interest in the Doukhobor cause, siding with them in cases of conflict with Canadian authorities.

He published articles and statistics for the Canadian government regarding immigration, wheat production, and workers' healthcare compensation.

[5] After he left, the University of Toronto for some time discontinued the tradition of extensive Russian studies he and William Ashley founded.