Stephen Pevar was born in Brooklyn, New York, in 1946. Pevar attended the University of Connecticut for two years and then transferred to Princeton University, graduating with a bachelor's degree in political science. He went on to earn his law degree from the University of Virginia School of Law.

He then served as a Legal Aid attorney on the Rosebud Indian Reservation from 1971 until 1974. In 1976, Pevar was hired as the Regional Counsel for the Mountain States Office of the American Civil Liberties Union. For over forty years, Stephen has worked as a staff attorney for the national office and the ACLU's Racial Justice Program.

Pevar is an expert on free speech, prisoners' rights and Indian rights, having written The Rights of Indians and Tribes in 2012. He currently teaches American Indian law at Yale Law School.