"I've missed them and I know they've missed me," he said.
"We feel that Dwyane can help our team in so many ways," Heat president Pat Riley said in the team's official statement. "It is a beautiful moment for us, for the city and for the fans. All of us embrace it in the manner that we want to win and that's why we brought Dwyane back home. We look forward to having a great end of season run as we fight for the playoffs."
Wade left the Heat in the summer of 2016 to sign a two-year, $47 million contract with the Chicago Bulls, but that partnership lasted just one season after the sides agreed to a buyout.
The 36-year-old inked a one-year deal with the Cavaliers, but he averaged just 11.2 points, 3.9 rebounds and 3.5 assists in a career-low 23.2 minutes per game.
Now back with the franchise that selected him fifth overall in the 2003 draft, Wade will presumably offer a boost off the bench and a strong veteran presence in the locker room as the Heat intensify their pursuit of a postseason berth.