Under the direction of Caldwell, in his first time calling plays at the NFL level, the Ravens have reached the Super Bowl while upgrading their offensive production and precision. And Flacco is playing arguably the best football of his career with 10 touchdowns and zero interceptions in the past five games.
"It's been fun," Caldwell said Sunday night at Gillette Stadium following a 28-13 victory. "It's been a great learning process for both of us. Joe's gotten to know me pretty well, and I've gotten to know him better. We've only been together a matter of months. It hasn't even been a year yet, so we're still in a growth process."
Flacco had a sterling second half against the Patriots, orchestrating a win where he tossed three touchdowns after halftime with the Ravens using a more free-wheeling offensive approach.
Flacco's last turnover was Dec. 16 in a loss to the Denver Broncos when he had an interception and lost fumble. He has been without a turnover in 19 consecutive quarters.
And this improvement followed a sputtering start to the Caldwell-Flacco partnership which began after offensive coordinator Cam Cameron was fired following an overtime loss to the Washington Redskins.
The Ravens' bold move to dismiss Cameron and replace him by elevating Caldwell from quarterbacks coach has paid dividends for the AFC champions.
And the Ravens are banking on Caldwell taking them to even greater heights in the future as they prepare to square off against the San Francisco 49ers' stingy defense in the Super Bowl. Ravens coach John Harbaugh announced Monday that Caldwell had accepted an offer to shed the interim label and go forward as offensive coordinator through at least next season.
The Ravens parted ways with Cameron on Dec. 10 after he spent five years with the team.
"It was a move that was the best move at the time, we felt," Harbaugh said. "We said that was the best thing for our football team. All the contributions and all the work that had gone into what we had done before that had gotten us to that point and put us in position to move on from there. To me, it all goes together. It was an important move."
Caldwell, 57, is known for his genial personality and a more democratic approach that incorporates input from assistant coaches and players.
"It's obvious to me from an X's and O's standpoint that Jim Caldwell has brought a certain amount of diversity into how the Ravens attack defenses that's also very deliberate," former Ravens offensive lineman Wally Williams said. "Cam was very bland where you knew what play they would run out of certain formations. Caldwell has been unpredictable. I don't think Cam was ready to take Joe to the next level. It was almost like he had a lock on Joe. I think they butted heads a little bit. They had to get rid of Cam.
"You don't always have to like who you work for, but you have to respect their opinion and where they're trying to take you as an athlete. If you feel like a coach is hindering your progress, you know what happens next. I think Cam was hindering Joe's growth. It came down to who was going to have the longevity in this program. Cam Cameron or Joe Flacco? You see what happened."
Caldwell understands what it takes to be an elite quarterback. He is a former Indianapolis Colts coach who reached a Super Bowl as their head coach and won one as the quarterbacks coach for Peyton Manning. Caldwell was hired by the Ravens after last season when he went 2-14 with Manning out for the entire season with a neck injury.
Whether on the field or in meeting rooms, Caldwell speaks in a relatively quiet tone. He's often characterized as a good listener.
"He's pretty dry," veteran center Matt Birk said with a laugh when asked about Caldwell's calm persona. "Since he's been through this a lot of times and has been a part of great offenses, he knows what it looks like and what it's supposed to feel like. Obviously, I'm sure he's drawing on his experiences and helping us out and bringing that to our offense."
Flacco appears to have a positive relationship with his new coordinator.
"I think we had a good relationship before he became coordinator, so I think he has settled in a little bit," Flacco said. "I think he has had the time to really prepare for it now, and I think we just continue to grow week by week."
The first sign that the switch to Caldwell had been a wise move was during a 33-14 rout of the New York Giants the week after losing to Denver. The Ravens piled up a season-high 533 yards of total offense with 224 rushing yards.
Against last year's Super Bowl champions, Flacco completed 25 of 36 passes for 309 yards, two touchdowns and no interceptions for a 114.2 quarterback rating.