Best known for his role in 2004 ice hockey film Miracle, Michael was found dead in his car this morning by police, according to TMZ.
The celebrity gossip site reported that a Washington State coroner said the cause of death was a self-inflicted gunshot wound.
Following his breakout role in Miracle, Mantenuto went on to join the army, later graduating to the Special Forces.
A skilled hockey player, it was his talent on the ice that led him to star alongside Kurt Russell in Miracle, which told the story of the 1980 US team which won gold at the Winter Olympics.
He starred as Jack O’Callahan, who played for NHL teams the Chicago Blackhawks and New Jersey Devils, in the film.
His next project was 2006 TV film, Dirtbags — a comedy featuring Sabrina The Teenage Witch star Melissa Joan Hart.
Michael’s final role came two years later in Surfer, Dude — a US comedy about a surfer experiencing an existential crisis starring Woody Harrelson and Matthew McConaughey.
His death was announced on Thursday morning by Col. Guillaume Beaurpere, the commander of Michael’s army unit.
This story originally appeared in The Sun and is republished here with permission.