After graduating from Notre Dame in 1978, Weis began his coaching career at Boonton High School in New Jersey. He spent the next five seasons at Morristown High School in New Jersey as a football assistant. In 1985, he was hired by head coach Joe Morrison at the University of South Carolina, where he served four seasons on the Gamecock staff before returning to New Jersey as the head coach at Franklin High School in 1989. That year, he directed Franklin Township to the New Jersey state championship while also assisting in the New York Giants' pro personnel department.