Raised on the Six Nations reserve near Brantford, Ontario, and a founder of the Committee to Re-establish the Trickster, he was educated at York University and the University of British Columbia. Dissatisfied with the tragic nature of many depictions of Indigenous people, he portrays instead an organic, living culture in his plays. His city plays, Coyote City (1988), Big Buck City (1991) and Kyotopolis (1992), which follow the adventures of an ever-expanding circle of characters, dramatize the processes through which Indigenous people can begin to heal their wounds.

To subvert the legacy of the tragic Indigenous person in Almighty Voice and His Wife (1991), Moses sharply divides the play: in the first act he recounts the history of a 19th-century Saskatchewan Cree folk hero, and abruptly shifts in the second to a grotesque vaudeville show performing a mixture of racial slurs, romantic clichés and puns. (See also Almighty Voice).

He has also written two books of poetry, Delicate Bodies (1980) and The White Line (1990), and co-edited An Anthology of Canadian Native Literature in English (1992). The Indian Medicine Shows: Two One-Act Plays was published in 1995.