Four years after leaving the Cavaliers to chase his first NBA title with fellow stars Dwyane Wade and Chris Bosh in Miami, an unapologetic James said he wanted to bring the long-suffering sports fans of his home region a championship.
James took a four-year deal worth $88 million with Cleveland over a five-year Miami offer worth $122 million and intends to finish his glittering career at the Cavaliers.
The dramatic move by the four-time NBA Most Valuable Player ended days of speculation about his free agency choice, which had Cleveland fans in a frenzy of anticipation.
"In Northeast Ohio, nothing is given. Everything is earned. You work for what you have," James, who grew up just south of Cleveland, in Akron, told Sports Illustrated in a first-person essay.
"I'm ready to accept the challenge. I'm coming home."
Celebrating in the streets of Cleveland, fans hailed "The Return of the King," the same streets where James jerseys were burned in 2010 after he announced he was ditching Cleveland for Miami.
By contrast, a wall painting in Miami depicting the entire Heat championship lineup had the face of James, the center figure of the mural, blackened out by vandals.
The 29-year-old won NBA crowns with Miami in 2012 and 2013, but lost in the 2011 finals, as well as to San Antonio in last month's finals, after which James opted out of his Heat contract to consider other offers.
Thanks to NBA salary cap rules giving teams a financial edge in trying to retain talent, Miami offered better terms, but could not offer the prospect of going home, James posting a photo of himself in a Cavaliers uniform on Instagram and Twitter with the phrase, "I'm coming home."
'Bigger than basketball'
James said he had followed his heart.
"I looked at other teams, but I wasn't going to leave Miami for anywhere except Cleveland. The more time passed, the more it felt right. This is what makes me happy," he said.
"My relationship with Northeast Ohio is bigger than basketball. I didn't realize that four years ago. I do now."
Las Vegas Hotel and Casino Superbook oddsmakers quickly made the Cavaliers a 3-1 favorite to win the 2015 NBA title, with Miami suddenly a 100-1 longshot.
But James warned: "I'm not promising a championship. I know how hard that is to deliver.
"We're not ready right now. No way. Of course, I want to win next year, but I'm realistic. It will be a long process."
James said bidding goodbye to Wade and Bosh and their Miami legacy was difficult.
"I believed we could do something magical if we came together. And that's exactly what we did," James said. "The hardest thing to leave is what I built with those guys."
Cleveland paved the way for James to return by opening salary cap space earlier this week in a three-team trade that sent veteran guard Jarrett Jack and guard Sergey Karasev to Brooklyn and forward Tyler Zeller to Boston.
James joins a young squad with new coach Dave Blatt, star guard Kyrie Irving and this year's top draft pick, guard Andrew Wiggins, that could be a contender for years to come.
"Excitement. Exhilaration and over-the-top happiness," Blatt said about bringing James on board. "He is the most versatile player in the world. He will help us determine what type of system we will play."
James becomes the central figure on the rising Cavaliers team that has owned the first overall pick in the draft three of the four years since he left.
"I see myself as a mentor now and I'm excited to lead some of these talented young guys," James said.
The wait for James to make his decision shut down most major free agency decisions in the league, and kept fans in Miami and Cleveland riveted to US sports television networks.
"I always believed that I'd return to Cleveland and finish my career there. I just didn't know when," James said.
Not since the 1964 Cleveland Browns won the National Football League crown has the city known a major sports champion.
But the once-derided "Mistake on the Lake" on the southern shore of Lake Erie is making a comeback, named this week as the site of the 2016 Republican National Convention and already the new home of American football star rookie Johnny Manziel with the Browns.
Cavaliers owner Dan Gilbert, who once called James a coward for leaving, tweeted: "My 8-year-old: "Daddy, does this mean I can finally wear my Lebron jersey, again?" ... Yes it does, son. Yes it does!"
James said he and Gilbert had made peace.
"I've met with Dan, face-to-face, man-to-man. We've talked it out," James said. "Everybody makes mistakes. I've made mistakes as well. Who am I to hold a grudge?"
James guided the Cavaliers to their only NBA Finals in 2007, where they were swept by San Antonio.