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, the Inyo County Sheriff said.
Officers sent a helicopter to locate his body and recover it.
It is believed Legeno, who was also a mixed martial arts fighter, died of heat-related issues, police said.
A sheriff's department spokesman said: "The remains have been identified as David Legeno, a 50-year-old United Kingdom man.
"It appears that Legeno died of heat-related issues, but the Inyo County Coroner will determine the final cause of death.
"There are no signs of foul play," he added.
Legeno was set to star in upcoming film Sword of Vengeance, produced by Vertigo Films.
Fellow Harry Potter star Tom Felton, who played Draco Malfoy, paid tribute to Legeno on Twitter.
He said: "Gutted to hear the sad news about Dave Legeno. He was a true Big, Friendly, Gentleman. Was a pleasure every time we met #BFG #DaveLegeno."
And later Felton posted an Instagram picture of the pair together on a publicity poster for the Harry Potter films, saying: "Dave Legeno. It was always a pleasure. He was a great talent with a heart of gold and always had time."
Legeno also appeared in Guy Ritchie's 2000 film Snatch and as a League of Shadows warrior in 2005's Batman Begins.