Harbaugh attended Miami University of Ohio, where he earned one football letter in his senior year.
"John didn't have blazing speed," said Steve Fitzhugh, a cornerback on that Miami team. "He wasn't the biggest, the strongest or the fastest. But he made up for it with hard work and dedication, and the rest of us could all feed off of that."
Said Jack Harbaugh: "John has tremendous energy and an enthusiasm unknown to mankind."
As a college senior, Harbaugh was named honorary captain for Miami's game against Western Michigan, then coached by his father.
On the opening kickoff, Harbaugh - a mainstay on special teams - lined up a few yards from the sidelines where his father stood.
Dad decided to mess with his son's head.
"John had his back to me, but I knew he could hear me," Jack Harbaugh said. "I told him, 'John, we've got a plan and we're coming for you.'
"John just leaned forward and hollered, 'Bring it!' "
For a moment, Jack Harbaugh's allegiance changed.
As the ball sailed downfield, he said, "I yelled to John, 'Go kick some [butt]!'
"Never mind that it was ours he was kicking."