The club announced late Monday afternoon that James put pen to paper on the reported four-year, $154 million deal, just as James' representation, Klutch Sports Group, tweeted an image of James, agent Rich Paul and Lakers general manager Rob Pelinka confirming the news.
"Today is a great day for the Lakers organization and Lakers fans all over the world to welcome LeBron James, a three-time NBA Champion and four-time NBA MVP," Lakers president of basketball operations Magic Johnson said in a statement.
"LeBron is special. He is the best player in the world. He loves to compete and is an awesome leader who is about winning and making sure that his team-mates are successful. The Lakers players are excited to have a team-mate who has been to nine NBA Finals. It's a huge step closer to returning the Lakers to the playoffs and to the NBA Finals."
James, 33, has averaged 27.2 points, 7.4 rebounds and 7.2 assists per game in 1,143 career contests. He also has been named NBA Finals MVP three times. Last season was his first in which he played in all 82 regular-season games, and the eighth in a row in which his team advanced to the NBA Finals (four in Miami before each of the past four seasons in Cleveland).
The Cavaliers had hoped to re-sign James, and the Philadelphia 76ers also had strong interest in the 6-foot-8, 250-pound superstar, meeting with James' representatives before he chose the Lakers.
Sixers managing partner Josh Harris said Monday, from summer league action in Las Vegas, that he thinks James gave serious thought to joining Philadelphia.
"I think they considered us very strongly," Harris said of James' group. "I think he -- I would be speculating on how he makes his decisions, and I don't want to do that -- but I think that they were really serious. The fact that they took the meeting with us was something that they didn't view lightly, so I think that they were very serious about it."
Joining the Lakers marks the first time James will play for a team in the hotly contested Western Conference, which includes heavyweight teams such as the Golden State Warriors and Houston Rockets. James spent his first seven seasons with the Cavaliers, his next four seasons with the Heat, and his last four seasons back at home with Cleveland.
Shortly after agreeing to terms with James last week, the Lakers agreed to deals with free agents Rajon Rondo, Lance Stephenson and JaVale McGee, and also agreed to bring back Kentavious Caldwell-Pope. Those deals were officially announced earlier this week.