British actor Legeno, 50, who played werewolf Fenrir Greyback in three Harry Potter films, was found in a remote part of Death Valley by a pair of hikers in the early hours of Sunday.
Felton, who played Draco Malfoy, paid tribute to Legeno on Twitter and Instagram.
"Dave Legeno. It was always a pleasure. He was a great talent with a heart of gold and always had time for anyone. Dave was a soft, kind gentleman off screen but had the skill to be the complete opposite on screen.
Legeno was set to star in upcoming film 'Sword of Vengeance', produced by Vertigo Films.
Legeno also appeared in Guy Ritchie's 2000 film 'Snatch' and as a League of Shadows warrior in 2005's 'Batman Begins'.