The 24-year-old center will earn $2.6 million next season, $3.3 million in 2018-19 and $3.4 million in 2019-20.
Pageau had eight playoff goals last spring as the Senators reached the Eastern Conference finals. He had 12 goals and 21 assists in 82 regular-season games.
“As an organization, we are thrilled that we got this contract done,” Senators general manager Pierre Dorion said.
“Arbitration is definitely a path we did not want to go down with Jean-Gabriel, especially the way he’s performed over the course of the last few seasons. He showed that he was definitely deserving of this contract.
“Any player that has a history of raising his game, whether it was in junior playoffs or [AHL] playoffs or NHL playoffs, I think you have to give credit for what he’s accomplished. We’re really happy to have him on board for the next three years.”
In 251 regular-season games, Pageau has 101 points (45 goals, 56 assists) and 71 penalty minutes.
Pageau had four goals — including the game winner — in Ottawa’s 6-5 double-overtime win over the New York Rangers in Game 2 of their conference semifinal. The Ottawa native, who grew up in nearby Gatineau, Quebec, has 16 points (12 goals, four assists) in 35 playoff games.
“We’ve always had a good relationship with Pierre, with [former GM] Bryan [Murray] before, with the team,” Pageau said.
“They always knew that I wanted to stay with the team. I take pride [in playing] for the Senators. So obviously, I think that helped get the deal done. I’m happy … to be here for the next three years.”
Pageau was drafted by the Senators in the fourth round (96th overall) of the 2011 draft.