There's also one thing that links them together. They were both born into football families and both seemed destined for long careers as players, coaches or administrators. Both of their fathers were assistant coaches at Stanford during some point in their careers.
David Shaw, meanwhile, was a wide receiver for Stanford under Denny Green and Bill Walsh between 1991-94. He began his coaching the following year, making stops in college and the NFL before joining Harbaugh at San Diego and following him to Stanford.
Shaw will be making his debut as a head coach Saturday when the Cardinal host San Jose State at 2 p.m. Until game day, it's business as usual.
"From the day I got the job I concentrated on what I had to do next," Shaw said. "There's still a lot to do before kickoff. If there is a moment, it might get emotional."
For two reasons:
Shaw named his father as an honorary captain of the contest and because it is the Bill Walsh Legacy Game.
"I named him the honorary captain not just for what he did for me but what he has done for Stanford," Shaw said. "He's been here twice (1974-76 and 1989-91) and the school has had some success each time. This is one of his favorite places on the planet. I wanted to honor him the first week."
The elder Shaw, although officially retired, continues to offer criticism of the day's practice.
"Dad comes out to practice and he's a cagey veteran coach," Shaw said. "He doesn't need to watch film. He sees it the first time. He tells me things he sees. It's a general exchange as we walk off the field. It's valuable to have that experience."
Shaw also finds himself channeling his father when he speaks to his own players. That's not unusual, he says.
"If any coach is being honest he will tell you we are all collaborations of all the coaches we've worked with," said Shaw. "When I talk I'll say something I remember Brian Billick said. I repeat things my dad said to me, not only about football, but about life. We are constantly using examples of our experience."
Walsh was also an important figure for Shaw, for whom he played three years and then shared office space when he came to Stanford.
"I've missed Bill every single day since he's passed," Shaw said. "I have a picture of him in my office and three at home. That's how much he means to me."
Walsh played and coached at San Jose State and coached at Stanford. He was a special assistant to the Athletic Director at Stanford at the time of his passing.
Shaw's head start into coaching should serve him well as Stanford faces a season full of expectations. The Cardinal recorded a school record 12 victories en route to the Orange Bowl championship, losing only to Oregon, which played in the national championship game last year, a game many expect Stanford has a chance to participate in this season.
"Last year was great but every team, every year, has to build its own momentum," Shaw said. "We have high aspirations and big goals but it comes down to hard work."
Stanford opens the season ranked seventh in the country. Shaw doesn't put much stock into the preseason poll. One of his former coaches reminded him that "if preseason polls can be used as toilet paper, at least they would be put to some use."
Shaw understands outside expectations better than most first-year head coaches. His father was a role model for hard work and a refusal to give into the high expectations from elsewhere.
"I'm so concentrated on what we have to do I don't even think about pressure," he said. I'm a coaches' kid. I'm relatively reserved. I'm a systematic, methodical human being. I don't get enamored with things. I was exposed to the NFL at an early age. It didn't faze me."
Players notice the difference between Harbaugh and Shaw, how the former seemed so animated. Shaw, so far, has been a model of steady pragmatism.
"Some things will happen with any coaching change, Stanford linebacker Shayne Skov said. "The mentality of the team will remain unchanged. We've been with him (Shaw) for a while. He's very thoughtful, competitive guy and players look up to him. He'll have tremendous success. He's a Stanford man."
The biggest difference for Cardinal quarterback Andrew Luck is interacting with Shaw less frequently.
"I see less of him than I thought," Luck said. "I guess as a head coach he has more responsibility than installing the passing game. He's up in his office more often doing whatever it is a head coach does. He's logical, thoughtful and we respect the heck out of him."