While working as a teacher in an Indian school, she began publishing short stories and autobiographical vignettes, which were published in various magazines in the east, including Atlantic Monthly. Her first book, Old Indian Legends, is actually a collection of folktales that she gathered during her visits home to the reservation.
In 1902, she moved to Utah with her husband, a Sioux employed in the Indian Service. Thus acquainted with the plight of native peoples across America, her writing became more politicized as she attempted to describe the problems she witnessed to the American public and to acquaint white America with the richness of traditional culture. The results were a highly syncretic form of writing, which included more folk tales and even an opera, Sundance (1913).
In 1916, Zitkala-Ša moved to Washington to work for the Society of American Indians. One of her most notable works, Oklahoma's Poor Rich Indians: An Orgy of Graft, Exploitation of the Five Civilized Tribes, Legalized Robbery was published there in 1924. This book was especially influential in winning Native Americans the right to vote. In 1926 she founded the National Council of American Indians and served as its president until her death in 1938, lecturing, writing, and bringing the story of the native people of the United States to the public. Zitkala-Ša was buried in Arlington National Cemetery. Her tombstone, which is engraved with a traditional teepee, is inscribed "Zitkala-Ša of the Sioux Nation."