Born in Milwaukee, Wisconsin, Risch is the son of Helen B. (née Levi) and Elroy A. Risch, a lineman for the local telephone company. His father was of German descent, and his mother was of Irish, Scottish, and English ancestry. Risch attended the University of Wisconsin–Milwaukee from 1961 to 1963 and then transferred to the University of Idaho in Moscow, where he was a member of the Phi Delta Theta fraternity. He obtained his B.S. degree in Forestry in 1965, and continued his education at the university's College of Law. He served on Law Review and the College of Law Advisory Committee before receiving his J.D. degree in 1968.