He rejoins a team where Kyrie Irving has stamped himself as a rising star, and the Cavaliers have added to his supporting cast, obtaining power forward Kevin Love - a US Olympic team-mate of James in 2012 - from the Minnesota Timberwolves to create a "Big Three" in the mould of the star trio James was part of in Miami along with Dwyane Wade and Chris Bosh.
The Cavaliers have further bolstered the team with sharpshooter Mike Miller, James Jones and veteran forward Shawn Marion, who helped Dallas win the 2011 NBA crown.
"I will be the leader of this team," James said. "I can lead by example, I can lead by voice, I can lead by command and I can lead by just my presence," said James, who will certainly be the key figure in the team guided by David Blatt - who will be coaching in the NBA for the first time.
The 55-year-old Blatt's standout international career included piloting perennial powerhouse Maccabi Tel Aviv to a 54-18 record in 2014, winning the Israeli League, Israeli Cup and the Euroleague title.
During his six years as head coach (2001-03 and 2010-2014), Blatt led the team to six Israeli Cups and five Israeli League Championships.
While Blatt is getting the feel of his new team in Cleveland prior to the start of the season in late October, back in Miami, coach Erik Spoelstra said the Heat will be back at square one, despite the leadership and experience of Wade and Bosh who opted to stay with the team.
"It's a new team really, we start almost from scratch," Spoelstra said. "But with DW and CB, we have two leaders, two cornerstones of our organisation, of its core values.
"We are in a great place to start a new era with high expectations."
-AAP