The 23-year-old left wing had a team-high 65 points in 79 games, and he was second in goals with 33 — two fewer than Erik Cole.
The deal, agreed to on Monday, is reportedly worth $27 million with an average of $4.5 million per season. Pacioretty will earn $1.65 next season (in the final year of his current deal), and the new contract will kick in the following season and run through the 2018-19 campaign.
The new contract was finalized two months after he won the Bill Masterton Trophy for perseverance, determination and dedication to the game. The 6-foot-2 Pacioretty broke his neck and sustained a concussion in March 2011 after taking a hit from Zdeno Chara, before returning to action last season.
Pacioretty, the No. 22 pick in the 2007 NHL draft, has 53 goals and 61 assists in 202 career games.