The 28-year-old was in the final season of a six-year contract he signed with the Ducks on Oct. 27, 2016, and could have become an unrestricted free agent after the season.
"They already have a championship-caliber team," Lindholm said Sunday. "I think any team I come to is going to be a better team. … I definitely think anywhere I go, I know I'm going to make a difference. I'm super excited to come to Boston. I think it's a good fit for me.
"It's not easy to extend your career that long in a place that you haven't maybe lived. But for me, I go with my stomach feeling. The team itself, it's a great team and I think they always have -- Boston as city and as a team and as an organization -- they always have that winning mindset. They find ways to get in the mix and compete and that's something that I always want to be. I love playing in the playoffs."
Anaheim received defensemen John Moore and Urho Vaakanainen, a first-round pick in the 2022 NHL Draft, a second-round pick in the 2023 NHL Draft and a second-round pick in the 2024 NHL Draft for Lindholm.
"I would be hard-pressed to think we were going to give away the assets, trade away the assets that we did without the belief that we could enter into an extension," Bruins general manager Don Sweeney said Sunday. "Obviously, the timing is difficult. You have to have some trust that your group is going to find some common ground after the fact, but we were confident in doing our diligence that this would be a place that Hampus would be excited to play."
The Bruins also received defenseman Kodie Curran in the trade. The 32-year-old, who has not played in the NHL, has scored 16 points (one goal, 15 assist) in 37 games with San Diego of the American Hockey League this season.
"We're a better team today," Boston coach Bruce Cassidy said Sunday. "[Lindholm] has a legitimate top-four (defenseman) resume in the National Hockey League. He's playoff-tested. Still young. Left side, so he'll either play with (Charlie) McAvoy or (Brandon) Carlo and probably both, to be honest with you, down the stretch here. See what best works for us once we get to know him as a player.
"But like I said, a real good add for us. Any time of year you've got to pay the price for a good player. 'Vaak' will get a chance now in Anaheim. He was practicing here, coming around. Johnny isn't practicing, but both good people we lose in the deal. But we gain a guy that's excited to come here. We exchanged some texts yesterday. I think he's ready to get here and get going. He won't be available tomorrow, but should be in the lineup Thursday (against the Tampa Bay Lightning)."
[RELATED: NHL Trade Tracker]
Lindholm has scored 22 points (five goals, 17 assists) in 61 games this season, including four power-play points. Cassidy expects him to play in all situations.
"He moves the puck well," Cassidy said. "He's been a power-play guy in Anaheim. … But at the end of the day, still a first pass, has some respectable offensive numbers. We'll see how he fits for us in that regard. … I think he's well over two minutes a game (on the penalty kill), so he's a good PK guy. He's going to be in there, helping us in that regard. So a lot of his strengths I think will translate to how the Bruins play as well, good defensive structure."
Selected by Anaheim in the first round (No. 6) of the 2012 NHL Draft, Lindholm has scored 222 points (57 goals, 165 assists) in 582 regular-season games and 21 points (four goals, 17 assists) in 21 Stanley Cup Playoff games.
"I'm a guy that wants to be known for making guys better out there," Lindholm said. "I think any guy I get to play with, I'm a guy that wants to be that kind of Swiss Army knife that you just fit into any role, that you can play anywhere, any minutes. That's something that's always been my strength and I value a lot as a D-man, to be the two-way defenseman that you can put anywhere, in any situation, to help the team win some hockey games. Coming to a team like Boston that's a bunch of winners and players that want to win makes me even more excited to jump on board here."
The Ducks (27-26-11) are seven points behind the Vegas Golden Knights for the second wild card into the playoffs from the Western Conference.
"Hampus has been a fixture with the Ducks for years, which we value and respect," Anaheim general manager Pat Verbeek said. "That said, we are very pleased with our return. As I've stated since arriving in Anaheim (hired Feb. 3), our goal is to continue building a team that can compete for the Stanley Cup for the long haul. Adding players and assets that fit in the age group of our existing younger talent sets us up well for the future."
Moore, 31 has one assist in seven games this season and has not played since Jan. 12. He has one season remaining on a five-year contract he signed with the Bruins on July 1, 2018, and can become an unrestricted free agent after next season.
Selected by the Columbus Blue Jackets in the first round (No. 21) of the 2009 NHL Draft, Moore has scored 118 points (38 goals, 80 assists) in 544 regular-season games with the Bruins, Devils, Arizona Coyotes, New York Rangers and Blue Jackets, and four assists in 49 playoff games.
Vaakanainen, 23, has four assists in 15 games this season and six assists in 31 NHL games. He is in the final season of his entry-level contract and can become a restricted free agent after the season.
The Bruins (38-19-5) are fourth in the Atlantic Division, nine points behind the first-place Florida Panthers, and hold the first wild card into the playoffs from the Eastern Conference. Boston has won 11 of its past 14 games (11-2-1).
"Bringing a player of Hampus's [caliber] and the age and where he's at in his career, I think it's ideal for our group," Sweeney said. "So I don't aspire to the window part of it. … Charlie [McAvoy is] signed long term. Brandon [Carlo] is signed long term. We've got foundational pieces that I think we're going to continue to be a really difficult team to play against."
On Saturday, Anaheim also traded forward Nicolas Deslauriers to the Minnesota Wild for a third-round pick in the 2023 NHL Draft.
Deslauriers has scored 10 points (five goals, five assists) in 61 games this season and 82 points (41 goals, 41 assists) in 486 regular-season games with the Ducks, Montreal Canadiens and Buffalo Sabres.
The 31-year-old forward is in the final season of a two-year contract he signed with the Ducks on Feb. 15, 2020, and could become an unrestricted free agent after the season.
Earlier in the week, the Ducks traded defenseman Josh Manson to the Colorado Avalanche on Monday for defenseman prospect Drew Helleson and a second-round pick in the 2023 draft.
NHL.com staff writer Amalie Benjamin contributed to this report