Harbaugh took over a 5-11 team, started a rookie quarterback and won 13 games, including two in the playoffs. His success appeared to justify the confidence of Ravens owner Steve Bisciotti and general manager Ozzie Newsome, who gave Harbaugh the job even though his previous pro experience was directing the special teams and secondary of the Philadelphia Eagles.
"They went out on a limb a little bit and chose to hire an unproven coach," Harbaugh said. "There's no I told you so that I'd admit to, but by the same token, from the beginning, my goal personally was to prove them right."
Harbaugh certainly made an excellent first impression. He intends to make a lasting one.
"Plenty of people are going to say we'll find out this year. Well, 10 years from now they'll be saying the same thing," Harbaugh said. "They talk about (Eagles coach) Andy Reid that way: Can he still do it? Does he still have it? I want to be talking 10 or 12 years from now about whether I can still do it. You don't prove anything in this league. You just have to move forward."
The Ravens worked hard during the offseason to take the next step. Newsome signed several free agents to address some of the team's shortcomings, most notably center Matt Birk, cornerback Domonique Foxworth, tight end L.J. Smith and kick returner Chris Carr.
The defense lost coordinator Rex Ryan, linebacker Bart Scott and safety Jim Leonhard. But Greg Mattison, who took over for Ryan, may have more to work with. Tackle Kelly Gregg and safety Dawan Landry, who didn't contribute last year because of injuries, are back. Tavares Gooden appears capable of filling the void left by Scott and rookie Paul Kruger should help Ray Lewis and Terrell Suggs in pressuring opposing quarterbacks.
During one of his first meetings with the defense, Mattison held the playbook aloft and said, "It doesn't really matter who is standing up in front of you, and it doesn't really matter what this playbook has. Because as long as we have the attitude and the players that we have, we're going to be successful."
Lewis, now entering his 14th season, wouldn't have it any other way - even in the preseason, when Baltimore ranked first in total defense and went 4-0.
Those numbers are meaningless, although it's worth noting the last time the Ravens went unbeaten in the preseason they won the Super Bowl.
For Baltimore to be successful in 2009, the defense must be its nasty old self and the offense needs to improve under second-year coordinator Cam Cameron and quarterback Joe Flacco.
"We've got to get better because we know there is no defense that is going to overlook us," Cameron said. "Maybe we got overlooked a little bit last year."
The Ravens hope Flacco will benefit from the experience he gained as an unexpected starter. The running game will again feature the three-pronged attack of Ray Rice, Willis McGahee and Le'Ron McClain, and the offensive line has been bolstered by the addition of Birk and first-round draft pick Michael Oher.
The wide receivers, however, remain one of the team's question marks. Flacco's options beyond the sure-handed, 35-year-old Derrick Mason are Mark Clayton, who missed the preseason with a strained hamstring, and Demetrius Williams, who has started only five games in three NFL seasons.
"We're OK with what we have," Harbaugh insisted.
Matt Stover is the only starting placekicker the Ravens have had, but this season the job belongs to Steve Hauschka, who handled kickoffs for Stover last year and missed only one field goal try during the preseason. Stover began to lose leg strength as a 40-year-old last year and was not re-signed, but is poised to return if Hauschka struggles.
If the offense and special teams can help out the defense, Harbaugh could come up with a decent encore to his memorable first season.
"If you're going to defeat us, you're going to defeat us as a team. There's no one side to any of this. When we step on the field, we're one heartbeat, bottom line," Lewis said. "Every year you feel confident, but with the young talent we've got now, why wouldn't I feel confident?"