Schmitz was born in Milwaukee, Wisconsin, the son of John G. Schmitz, former California State Senator, member of the U.S. House of Representatives, and U.S. presidential candidate in 1972. Schmitz attended Catholic schools as a child, and Georgetown Preparatory School for high school, a time period in which his father also served in Congress. He holds a Bachelor of Science (1978) from the United States Naval Academy in Annapolis, Maryland, where he was on the wrestling team, and a Juris Doctor (1986) from Stanford University. His three siblings include: Mary Kay Letourneau, Jerome Schmitz, and John Schmitz.