Jack Avon Harbaugh is a former American football player and coach, and the father of the first pair of brothers to serve as NFL head coaches and the first pair of head coaching brothers to face off in a Super Bowl: John and Jim Harbaugh.

From 1982 to 1986, Harbaugh served as the head football coach at Western Michigan University and compiled a 26–26–3 record. From 1989 to 2002, he was the head football coach at Western Kentucky University. During his tenure with the Hilltoppers he posted a 91–68 record, including three 10-win seasons. In 2002, the WKU squad won the NCAA Division I-AA national football championship.

After leaving Western Kentucky, Harbaugh served as an associate athletic director at Marquette University, Milwaukee, Wisconsin, where his son-in-law, Tom Crean, was the head coach of the men’s basketball team. Harbaugh has also served as an assistant coach at Morehead State University, Bowling Green State University, the University of Iowa, the University of Michigan, Stanford University, the University of Pittsburgh, and the University of San Diego.

Harbaugh retired in 2006, but served as Stanford’s running backs coach in the 2009 Sun Bowl under his son, Jim.