By the late 1870s, Wallace had become involved in the women's suffrage movement. In April 1878 twenty-six people who attended a meeting held at Wallace's home agreed to form the Equal Suffrage Society of Indianapolis. Wallace was elected as the group's president; May Wright Sewall, who initiated the group's first meeting a month earlier, was elected secretary. For nearly a decade the Indianapolis suffrage group did not formally join a specific suffrage organization at the national level. Instead, the Society preferred to work with several different groups that were politically active in lobbying, letter-writing campaigns, gathering petitions, and speechmaking on behalf of women's suffrage. The Society finally affiliated with the National Woman Suffrage Association in 1887.