In 1967, Steinhardt met his future wife Judy in a car pool he organized. During one of the carpools into New York City, he mentioned the name of the grain elevator company Colorado Milling and Grain Elevator. Judy mentioned the company to her father who invested in the company and made a substantial profit after Colorado Milling was acquired by Great Western Sugar in 1968; the merged company was renamed Great Western United. Judy is the chairwoman of New York University's Institute of Fine Arts and of the American Friends of the Israel Museum. They have three children: David, Daniel and Sara. His daughter, Sara Berman, a former journalist and parenting columnist for The New York Sun, is married to Mark Bloom and is the president of the Hebrew Language Academy Charter School in Brooklyn.