The forward, who was a restricted free agent, had been scheduled for an arbitration hearing Thursday.
"We're very happy to have Connor back under contract," Senators general manager Pierre Dorion said. "He brings a veteran presence to our lineup and is a player who can play in different situations. He's durable, has a strong work ethic with great practice habits and is regarded as a leader by his teammates. His ability to play up and down the lineup while producing offensively is especially valuable to us as we continue our transition towards being a consistent winner."
The 26-year-old scored an NHL career-high 43 points (16 goals, 27 assists) in 71 games with the Senators last season.
"The negotiations were a little nerve-wracking," Brown said. "It was kind of a bit of a roller-coaster ride. I think, especially given all the circumstances with just the uncertainty of the world right now, I think that obviously played a part. But obviously it's just very exciting. You feel relieved and excited that it's all settled, and I can just think about training and getting ready for next season."
Selected by the Toronto Maple Leafs in the sixth round (No. 156) of the 2012 NHL Draft, Brown has scored 142 points (59 goals, 83 assists) in 324 regular-season games with the Maple Leafs and Senators and has has scored five points (one goal, four assists) in 20 Stanley Cup Playoff games.
Ottawa (25-34-12, .437 points percentage) finished 15th in the Eastern Conference last season and was not among the 24 teams that competed for the Stanley Cup under the Return to Play Plan, missing the playoffs for a third straight season.
As for how he expects the Senators will fare over the next three seasons, Brown said, "It's hard to predict right now because a lot of the young kids like (22-year-old forward Drake Batherson) and (21-year-old forward Josh Norris) and these guys are just getting going. So whether they step in right away and they're impactful players right away or they need some time, I mean, that's going to be dependent on how our team does. It's hard to predict, but I believe that we've got good people. I believe in the coaching staff. I think we've got good guys in that room and we'll be doing things the right way. And hopefully it turns around quicker. Obviously as quick as possible."
NHL.com staff writer Mike Zeisberger contributed to this report
