 Wallach was born in Superior, Arizona, the son of Albert Wallach, a millworker at the Magma Copper Company, and Sara Wallach, a local artist who helped run the town library and Little Theater group.Wallach was decorated for his service in the United States Army during the Vietnam War, and received a Bachelor of Arts degree at the University of Arizona in 1973, followed by a Juris Doctor at the University of California Berkeley in 1976.Wallach joined the firm of Lionel Sawyer & Collins in Las Vegas, Nevada, as an associate, in 1976.