Marie began her career in the late 1880s first in her native Brooklyn and then on Broadway. In 1902 in the show Sally In Our Alley she introduced the song Under The Bamboo Tree which became her signature song and one of the most famous songs from the turn of the century.
Also in 1902 in the musical The Wild Rose she premiered another hit song Nancy Brown. In 1903 the popularity of the Nancy Brown song was expanded into its own musical for Cahill, and became her favorite role. She had a plump and jolly demeanor and in addition to being a singer she presented herself as a conversationalist in a style that at best anticipates the later Gracie Allen.