MacKaye first intended to be a concert pianist, but in 1907, she enrolled in Radcliffe College theater classes taught by George Pierce Baker.

MacKaye also acted, touring with the Castle Square theater company of Winthrop Ames and appearing in her brother's Sappho and Phaon and Jeanne D'Arc (both 1907) and Mater (1908).

The organizers of the Woman Suffrage Procession, planned for Washington, D.C., on March 3, 1913, just before Woodrow Wilson's inauguration, asked MacKaye to create a pageant for the event.

Titled Allegory and produced by director Glenna Smith Tinnin, it was presented on the steps of the U.S. Treasury Building as the culmination of the event.

[3] Later that year, MacKaye and Tinnin collaborated again, creating the pageant Uncle Sam's 137th Birthday Party to celebrate Independence Day on July 4, 1913.

Her 1915 production Susan B. Anthony, presented at Convention Hall in Washington, D.C., was more successful, raising money for Paul's Congressional Union and celebrating the life of the great early leader of women's suffrage.

In 1921, MacKaye and Marie Moore Forrest were in charge of the ceremony for the presentation of Adelaide Johnson's "Portrait Monument to Lucretia Mott, Elizabeth Cady Stanton, and Susan B. Anthony" to the U.S.