Born in northern Nevada in 1946, Louis is the eldest of twelve children. Of mixed heritage, Louis is of Lovelock Paiute descent. He moved from Nevada to South Dakota's Pine Ridge Reservation.
Louis graduated from Brown University with a Bachelor's and MA in Creative Writing. Louis was also a former journalist and along with being editor of four tribal newspapers, he was the managing editor of Indian Country Today and a co-founder of the Native American Journalists Association.
Louis has ten published books of poetry and two novels, including Blood Thirsty Savages by Time Being Books, in 1994. His poetry and fiction have garnered him much recognition and awards. His work has been praised by some of the other notable modern Native American writers, including Sherman Alexie, N. Scott Momaday, James Welch and Leslie Marmon Silko. In 1999, he was added to the Nevada Writer's Hall of Fame. In 2001 he was awarded the Writer of the Year by Wordcraft Circle of Native Writers and Storytellers and the Cohen Award for best published poem in Ploughshares. He is also the recipient of the Pushcart Prize as well as fellowships from the Bush Foundation, the South Dakota Arts Council, the Nebraska Arts Council, the National Endowment of the Arts and the Lila Wallace–Reader's Digest Foundation.
Louis taught English at Pine Ridge's Oglala Lakota College from 1984–1997; since 1999, he has taught in the Minnesota State University systems.