The deal, worth $15 million, according to a source close to Bergeron, will keep the 25-year-old forward in Boston through the 2013-14 season.
"I knew it was going to get done, because at the end of the day I was the one who was going to say yes no matter what," Bergeron said Friday. "I just feel comfortable in Boston, it's my home now. I just wanted to stay in Boston and I think [general manger] Peter [Chiarelli] and the Bruins knew it all along."
A second-round draft pick in 2003, Bergeron has 99 goals and 181 assists in 376 career regular-season games, as well as five goals and 15 assists in 31 playoff games.
He had 19 goals and 33 assists last season to tie David Krejci for the team lead with 52 points.
"He's got a lot of elements to his personality, to his game, that are terrific, really," Chiarelli said Friday. "When you look at this work ethic in practice, look at him doing the drills, day to day showing up and getting them right and leading the charge, he's a consummate professional and a terrific player and a terrific young man."
There were smiles all around the Bruins' dressing room and during a news conference following the team's final practice in preparation for their season opener Saturday morning at the O2 Arena against the Phoenix Coyotes.
The sight of a strong, healthy Bergeron was a sharp contrast to the scene three years ago when a pale, dazed Bergeron in a neck brace struggled to answer questions after suffering a Grade 3 concussion on Oct. 27, 2007. He missed most of the 2007-08 season.
"When it first happened there was obviously fear in everybody and I still remember that arena being so quiet," coach Claude Julien said Thursday, thinking back to the day when Bergeron lay motionless on the ice after taking a hit from behind in the corner that propelled him head-first into the boards.
"As a coach and players, it really rattled the whole bench, and the first thing you want to do when the game is over is not even talk about the game but go and see and make sure he is fine because it was a real, real close call. That was one that could have easily ended his career, and the thing that we wanted to do was make sure that Bergy the person was being taken care of first and foremost."
Bergeron took the proper recovery routes and even tried to make a comeback for the Bruins' first-round playoff series against the Montreal Canadiens in April 2008, but he wasn't ready.
"We were going to be as patient as we needed be and we were going to be as supportive as we needed to be," Julien said. "He never played the rest of that year and I know at one point he wanted to come in and play in the playoffs but at that point we made a decision that it was better off not to and wait a little more."
The following season Bergeron returned to the ice, but he struggled to regain his game and utilize the skills that had produced a 70-point season prior to the injury in 2006-07. In December 2008, Bergeron took an open-ice hit to the head from current teammate (then with the Philadelphia Flyers) Dennis Seidenberg that resulted in another concussion.
After taking some time off, Bergeron came back and, this time, looked like the two-way player who showed so much promise, finishing the season on a tear and helping lead the Bruins to Game 7 of the Eastern Conference semifinals before they fell to Carolina in overtime.
"The way he has bounced back, and you look at that following year [2008-09], and when you've sat out the previous year, you get off to a slow start, and we could see he was trying to find his game," Julien said. "Then he suffered that second concussion and you start to worry again, but he came back and his game really picked up from there. By the end of the year he was arguably our best player."
Asked about the way he has battled back since those two concussions, Bergeron credited others, pointing to older teammates who have guided him along the way and to the Bruins' organization for treating him with class and dignity.
"On and off the ice, I've learned a lot from the older guys like Mark Recchi and Glen Murray when he was with us and Martin Lapointe," Bergeron said Thursday. "All of the experience I've gotten got me where I am now, and obviously the adversity I faced with the concussions, it's something that made me be stronger and made me realize that hockey is my passion. I appreciate every day even more now.
"The Bruins organization has been awesome since Day 1. They drafted me, they took care of me and that's where I wanted to be. Especially after my injury, they made sure I was back to 100 percent and they talked about the human being before the hockey player first and that was something that was pretty special to me."
Chiarelli acknowledged that Bergeron, who entered the NHL in 2003 as an 18-year-old rookie, has come a long way.
"He's aged -- he's still a young man -- but he's much more mature," Chiarelli said.
"He's a very intelligent young man and to watch him grow up in the time that I've been here has been a pleasure," he added. "I hope to watch him grow to an old man."
James Murphy covers the Bruins for ESPNBoston.com. Material from the Associated Press was used in this report.