The Harbaugh brothers grew up around one of the legends of college football, Bo Schembechler, at the University of Michigan.
Jack Harbaugh was one of Schembechler's assistants from 1973-79.
In 1973, John was 11 and Jim was 10, so the two of them spent their prepubescent and teenage years under the influence of one of the most influential men to ever coach the game of football.
One story from their time at Michigan features the younger Harbaugh, per The Detroit News' Angelique S. Chenglis:
Then there's the famous story about 12-year-old Jim, who entered Schembechler's empty office, sat in the chair and propped his feet on the desk. Schembechler, who had been playing racquetball with Jack Harbaugh, walked in.
"Well, how are you doing today, Jim?" Schembechler said, according to a Los Angeles Times interview with Jim Harbaugh in 1986.
"I'm doing fine, Bo, how are you doing?"
Jim was never one to be timid, even in his youth. The elder brother has always been a bit more reserved, as Chenglis writes:
Countless stories have been told about how John Harbaugh would attend Michigan practices, and when he wasn't running around and goofing off, he was actually paying attention and would ask questions of the coaches, including his father.
He relished those days and often has talked about being taped to the goalpost and stuffed in lockers by Michigan players, calling that "a privilege."
It's clear that the brothers were inundated with football culture from a young age, and their time spent with Schembechler has served them well throughout the years.