"Ever since Day One, this city has welcomed me with open arms and I love being here," the 22-year-old forward said. "I said before this whole process began, I love everything about being in Ottawa. I love the people, the community, my teammates, the coaching staff, management, ownership. It's the place I wanted to be for a long time and I'm glad it all worked out the way it did, and I'm definitely really happy."
Tkachuk, who was a restricted free agent, led the Senators with 36 points (17 goals, 19 assists) in 56 games last season. He also led them in penalty minutes (69) and was second in the NHL in hits (248), two behind Florida Panthers defenseman Radko Gudas.
"This is an exciting day for the Ottawa Senators," general manager Pierre Dorion said. "Brady possesses a very dynamic skill set and is a prototypical power forward in today's NHL. He scores goals, he plays physical and exemplifies what it means to be a pro for all players in our organization.
"It's another piece. Another, I would say, big piece, in the puzzle of us trying to build a winner. Words can't describe, I think, the impact that Brady brings in a game. He just drags us into the war every night. And there's a lot of games that are wars, and a credit to him. I think there's a lot of intangibles that aren't measurable about Brady."
Coach D.J. Smith had previously said it would take Tkachuk 7-10 days to be game-ready after missing all of training camp.
"I definitely missed being a part of the team and missed my close buddies here," Tkachuk said. "I missed meeting the new guys too. So it was tough kind of being away, but now I'm just glad you know the business side is done with, and I don't have to think about that for a while, just get to be with the group, be part of the team again and improve every single day and just try to do what I can to help."
Ottawa (2-1-0) split a home-and-home against the Toronto Maple Leafs and defeated the Dallas Stars 3-2 on Sunday without Tkachuk to begin the season. It next plays Thursday against the San Jose Sharks at home.
"The one thing that always impressed me throughout this process is hearing from the other side about how much Brady wanted to be here long term," Dorion said. "And that's why we were never worried that we weren't going to be able to do a long-term deal. And that says a lot about him.
"He's the one that drives the bus for our team. He brings us into battle every night. And to get it done for seven years I think is a great thing for the organization."
Selected by Ottawa with the No. 4 pick in the 2018 NHL Draft, Tkachuk has scored 125 points (60 goals, 65 assists) in 198 NHL games.
"I give a lot of credit to Brady. Players can choose how long they want to be here," Dorion said. "It might have taken a bit longer than I think both sides wanted it to ... but we did it right. And to me, that is the most important thing. And our fans benefit from it, the organization benefits from it, I think everyone benefits from it."
NHL.com independent correspondent Callum Fraser contributed to this report
