Butler and Justin Patton were traded to Philadelphia in exchange for Robert Covington, Dario Saric,Jerryd Bayless and a 2022 second-round draft pick.
Butler will be introduced by the 76ers on Tuesday and is expected to debut with his new club on Wednesday at Orlando. Philadelphia is playing Monday at Miami.
"I'm ready to get started," Butler told NBC Sports Philadelphia upon arriving at the airport. "We got a little ways to go. We got some things to figure out. But all in all, I look forward to it."
The deal gives Philadelphia a legitimate Big Three, with Butler joining All-Star forward Joel Embiid and reigning rookie of the year Ben Simmons on a team that was expected to be a major Eastern Conference contender this season.
"We have a championship window that's centered around the continued progression of our talented young core, as well as our ability to add elite players who elevate our program," 76ers general manager Elton Brand said. "In Joel Embiid and Ben Simmons, we have two of the NBA's top-20 players. Now we've added a third top-20 player in Jimmy Butler, who is one of the NBA's very best on both ends of the floor."
The 76ers won 47 games in a three-season span between 2013 and 2016. They won 28 in 2016-17, made the jump to the playoffs at 52-30 last season and now will be considered an even more serious threat to emerge as the East rep in the NBA Finals.
"The biggest challenge is piecing all this together," 76ers coach Brett Brown said. "It's not even close. ... I say that completely from an excitement standpoint. This isn't a burden. Sure, it's a responsibility. But I'm excited with piecing this together."
"I think he's going to bring toughness, scoring ability, a veteran," 76ers guard Markelle Fultz said after the team's shootaround on Monday in Miami, shortly before the deal was formally announced. "Just going to compete on both ends of the floor, and I hope he pushes this team to a higher level."
Butler has averaged 21.8 points per game since the start of the 2014-15 season, the 13th-highest clip in the NBA in that span.
There are three teams with multiple teammates averaging at least that many points in those seasons. Golden State has three such players, with Stephen Curry, Kevin Durant and DeMarcus Cousins, though Cousins hasn't played yet for the Warriors while recovering from surgery. Oklahoma City teammates Russell Westbrook and Paul George also have averaged that much, and now Philly has such a pairing in Butler and Embiid.
Butler is the obvious headliner to this trade, though there will be some adjustments for the 76ers to make now that the deal is done.
Saric and Covington were key players for Philadelphia, combining to make 398 starts including playoffs during their time with the club. Saric averaged 13.5 points with the 76ers over parts of three seasons, while Covington averaged 12.9 points during his five seasons with Philly. They were the starting forwards for the 76ers in nearly every game last season, when Philadelphia had its best record since 2000-01 -- the last time the franchise went to the NBA Finals.
The deal between the teams was struck Saturday, but it couldn't become official until Monday, when the NBA had what's known as a trade call -- in which all the terms of the swap are reviewed to ensure that the deal is permissible under league rules.
It ends a two-month saga in which there was little doubt that Butler was going to be traded out of Minnesota. He told the Timberwolves shortly before training camp that he wanted to be moved, which forced Minnesota's hand because it was clear that Butler would not re-sign there next summer. As such, the options were move him for something or lose him for nothing.
"He loves to win," Fultz said. "He's going to do whatever it takes to win."
Asked what Sixers fans can expect from him, Butler said, "Hard playing. A guy that wants to win. We got some things that we want to get done here. We want to win. We want a championship.
"I think the core group of guys that we have, we'll figure out a way to get it done."
The Associated Press contributed to this report.
Woj: Butler has to make it work with Sixers
ESPN's Adrian Wojnarowski discusses the Jimmy Butler trade and how Butler has to make it work with Philadelphia.