Black Elk was born in 1863 into the Oglala Lakota, present as a boy near the Battle of the Little Bighorn in 1876 and a survivor, as a young man, of the massacre at Wounded Knee in 1890. He later toured Europe for a period with Buffalo Bill's Wild West show. In 1904 he was baptized into the Catholic Church and worked for decades afterward as a catechist among his own people, a fact that later scholarship, notably Raymond DeMallie's critical edition of the interview transcripts behind the published accounts, treats as a genuine complication rather than a simple conversion story: Black Elk continued to hold Lakota religious authority and knowledge throughout the period of his Catholic service, and how the two commitments related to each other in his own understanding remains debated among scholars rather than settled.
His first extended public account came through the poet John Neihardt, who interviewed him in 1930 and 1931 and published the result as Black Elk Speaks (1932), a book that became, and remains, the most widely read single work associated with Lakota religion, for better and worse: it also reflects Neihardt's own literary choices as much as a direct transcript.
His long life meant he was among the last living witnesses of pre-reservation Lakota religious practice by the time later scholars and interviewers sought him out, a circumstance that gives his testimony particular weight in reconstructing practices that had otherwise gone undocumented by outsiders.