"That was huge," Harbaugh said of Reid's ability to take control of the locker room as a rookie head coach. "Having gone through that, that gave me strength.
"The thing Andy did, he never backed down from anything he thought was right. ... There were probably four or five run-ins with veteran guys where Andy just stood up, didn't take a step back and said, 'This is how we're going to do it.' That was encouraging to me to come in here and know that I was going to do that."
Reid had to overturn his first Eagles roster. Harbaugh, inheriting a losing team filled with accomplished veterans, had to reshape his. He didn't publicly punish or criticize any players during camp, but he established a similar tone with his demanding and physical practices.
It was exactly what owner Steve Bisciotti and general manager Ozzie Newsome wanted to see.
"We truly endorsed basically everything [John] wanted to do with the locker room, with the signs in the hallway, all those things, and how he wanted to go about the practices," Newsome said. "Because we felt like, No. 1, the players would respond to it. And the ones that didn't would weed themselves out. We felt it was the right way to go about getting this organization from a football standpoint back on the right track."
The Ravens responded by winning six of their first nine games and are just a game behind the Pittsburgh Steelers in the AFC North at 6-4. Reid went 5-11 his first season, then jumped to 11-5 and a playoff berth in 2000.
"I'm proud of what he's done," Reid said of Harbaugh's start. "I'm proud of the players who have rallied around him. That's very impressive to me. ... He's a great football coach. He could coach any position on the field and have success with it."
Ravens offensive coordinator Cam Cameron, who once hired Harbaugh for his Indiana University staff, sees a similar toughness in mentor and student.
"You just see a mental toughness and an ability to lead men," Cameron said. "I've always thought Andy Reid did an outstanding job of that, and I know John always had those characteristics to a degree."
In Baltimore, Harbaugh knew he had talented players. His thrust was to give them more direction, rather than a new identity.
"I wanted our kind of players," he said. "I think Ozzie, Eric DeCosta [director of college scouting] and really, the previous coaching staff, they've established a certain type of mind-set, a certain kind of player. That's not exactly what we wanted here. We wanted to move that a little bit in a certain direction. But the foundation - tough, hard-nosed guys - that's been in place here a long time."