James' representatives at Klutch Sports Group tweeted a picture of James signing his new contract with the Lakers, alongside his agent, Rich Paul, and Lakers general manager Rob Pelinka.
The four-time MVP victor has played in the past eight NBA Finals with the Heat and the Cavs, winning three titles during that period.
"He competes and is an incredible leader who only seeks to win and make sure that his team-mates are successful. It's a huge step closer to the playoffs and to the NBA Finals".
The Lakers, who dominated the National Basketball Association in the 1980s behind the brilliance of Johnson and Kareem Abdul-Jabbar and again in the early 2000s with Kobe Bryant and Shaquille O'Neal, have missed the playoffs the last five seasons.
James, 33, has averaged 27.2 points, 7.4 rebounds and 7.2 assists per game in 1,143 career contests.
Many NBA fans have known for months, nearly a year, that LeBron would be joining the Lakers this summer.
At 38 years old and with two years of head coaching experience, Walton is extremely young and was actually in the same 2003 NBA Draft class as James.
"This is a historic moment for the Lakers and we could not feel more grateful and honored", Pelinka said.
Most would tell you the Philadelphia 76ers never really had a shot to land LeBron James in free agency.
James played in all 82 games last season, tallying a team-high 27.5 points (third in the NBA), acareer-high-tying 8.6 rebounds and a career-high 9.1 assists (second in the NBA) while shooting54.2 percent from the field.
And we, happily, all know how that turned out. "When LeBron James - a perennial NBA MVP and champion who is playing at the most astonishing levels of his career - chooses to join the Lakers, it serves as the ultimate validation for what we are building here". The game proved to be James's final appearance for the Cavs as he signed a four-year deal with the Lakers this month.