The couple moved to Montreal, and May set up a Baháʼí center in her home. Prior to 1912, she supported a Children's Court for Montreal, and her efforts were chief in maintaining the Colborne Street Milk Station. In about 1914, she brought a Montessori teacher from New York to their home in Montreal to start the first school of this type in Canada. In Montreal May continued to convert people such as Arthur Armstrong, Rose Henderson and her husband's cousin Martha MacBean. In 1912 ʻAbdu'l-Bahá visited Canada and stayed with the Maxwells. She was an early participant at Green Acre, the first Baháʼí training facility in the United States. In 1927 she was a member of the US and Canada National Spiritual Assembly.