The deal has an annual average value of $6.125 million per season with a full no-movement clause for the first five years and a modified no-trade clause for the remainder of the deal, according to multiple reports and confirmed by ESPN.
"This is an extremely exciting day for me and my family," Marchand said. "I would like to thank the Jacobs family, Cam Neely, Don Sweeney, Claude Julien, the coaching staff, my teammates and our fans for their continued support and belief in me. I have been a Bruin since the start of my pro career and there is no place I would rather play. I look forward to doing everything I can to help our team achieve success and bring the Stanley Cup back to Boston."
Marchand, 28, played in 77 games last season, scoring 37 goals with 24 assists and a plus-minus of 21.
The three-time All-Star has 153 goals and 136 assists in seven seasons, all with the Bruins.
Marchand scored two goals Saturday to help Team Canada advance to the World Cup of Hockey final with a 5-3 victory over Russia.
Bruins general manager Don Sweeney had said that signing Marchand was a priority, since he had one year remaining on his current deal.
It was also important to get it done now because he is enjoying tremendous success playing alongside Sidney Crosby for Team Canada. Marchand has three goals and two assists for five points in four games for Team Canada.
"[Marchand is] an amazing player I really enjoy to play with, and we've created a lot of chemistry over the years. I was getting a little worried now with him playing with Sid," Bruins center Patrice Bergeron said with a laugh. "I'm really happy it's done and we can move forward for himself and also for us as a team. I can't say enough about him. It's well deserved and he's an amazing player."
When asked recently about the possibility of signing elsewhere, Marchand said: "That's a long ways away, but there's a championship games here, we got to think about that first. But we'll deal with whatever needs to be dealt with down the road. But it's a lot of fun playing with Sid, there's no question about that. But for now we'll keep that to here."
Marchand was also motivated to get a deal done in Boston for the chance to play with Bergeron for the foreseeable future.
"It's pretty impressive the way he's improved," Bergeron said. "I've always thought he was an amazing player to play with, and the way he's handled himself on the ice night in and night out, he's always been first on pucks, working hard, competing and all that, I just think he's improved his game from one year to another. He got 37 goals last year, and it wasn't a fluke. Obviously, we're seeing that right now. It's great to see."