Lehner played a career-high 36 games last season with a record of 12-15-6 with a 3.06 goals-against average and a .913 save percentage.
"I'm very, very happy that it got done," Lehner said Thursday. "It's been a long summer, I've been quite anxious to get it done. I feel like part of the team and the community again. So yeah, I'm very happy."
The deal is worth $1.5 million, $2.02 million, and $3.15 million, respectively, in each season, a source told ESPN.com's Pierre LeBrun.
In 61 regular-season games with Ottawa, Lehner has a record of 21-24-10, with a 2.82 GAA and .918 save percentage.
Lehner was selected by Ottawa in the second round (46th overall) in the 2009 draft.
The Associated Press contributed to this report.