While the franchise has a habit of bringing back familiar faces, whatever happened to Leon after the original The Fast And The Furious? The first movie was a modestly budgeted action film that was basically a loose remake of Point Break, but with cars instead of surfing. The movie leaned on its action and the charisma of stars Vin Diesel and Paul Walker. While Walker returned for the fabulously titled 2 Fast 2 Furious, Diesel opted out to make xXx instead. The series was appearing to wind down by third entry The Fast And The Furious: Tokyo Drift, but the positive response to a surprise cameo by Diesel convinced Universal to keep going.
The original cast reunited for 2009's Fast & Furious, and the surprise success of that film convinced the studio to go even bigger. Dwayne Johnson was added to Fast Five, and the series has gone from strength to strength ever since. The drama gets soapier and the action more insane, but audiences keep coming back. The franchise also received its first spinoff with Hobbs & Shaw in 2019, which teamed Johnson's hulking agent with Jason Statham's antihero. The main series is set to come to a close with the forthcoming Fast & Furious 9 and 10.
Family is a core theme of the series, both in front of and behind the camera. This is one reason why even minor characters recur throughout the series, with a key example being Matt Schulze's Vince. This character was part of Dom's crew in the original, before reappearing in Fast Five and sacrificing himself of the team. One character whose fate has yet to be addressed in any way following the first movie is Leon, played by Johnny Strong (Black Hawk Down).
Leon was another member of Dom's crew and acted as dispatcher. He also took part in The Fast And The Furious' big truck heist. He splits from the group after the heist goes very bad and that's the last anybody saw of him. While Strong still acts, he's mostly focused on his music career, and in an EW interview admitted he doesn't know what happened to Leon either. He feels that since Leon objected to the heist that Dom insisted on - which quickly went south - the character made the smart choice to just split. The killing of Jesse by Johnny Tran in the finale likely reinforced that decision.
In all likelihood, Leon was never brought back to the Fast & Furious saga since he's a minor character from a time when the series at least tried to adhere to the laws of gravity, so there was no real place for him. In the same interview, Strong mentioned he'd be up for a return under the right circumstances and possibly as a villain, but while he appreciates fan interest in Leon, he doesn't seem particularly invested in a return either. With at least two more movies - and likely a few more spinoffs - odds are good Leon's fate with be resolved in a future Fast & Furious one way or another.