Jeremy Renner’s horrific snowplow mishap occurred while the “Avengers” star was acting as a good Samaritan to a stranded motorist, the mayor of Reno, Nev., has revealed.

“He was helping someone stranded in the snow,” Mayor Hillary Schieve told the Reno-Gazette Journal. “He is always helping others.”

During a Monday night interview, Schieve said she was friends with Renner — who has a home in Washoe County, which covers Reno — and described him as an unsung, real-life hero who supports many local charities.

“He’s always calling and saying, ‘Hey mayor, what do you need?’” she said.

“There are a few times he’ll post about what he has done or donated toys, but most of it you would never know he is doing.”

Renner, 51, was in critical but stable condition Tuesday following surgery for injuries sustained when his massive, tread-operated PistenBully snowplow ran over him around 9 a.m. Sunday near Mt. Rose Highway.

In a statement Monday, a spokesperson for the actor said that he’d “suffered blunt chest trauma and orthopedic injuries” in the freak accident.

Renner had reportedly been plowing a pathway on his property after a storm dumped at least 3 feet of snow on the area.

A neighbor said Renner “likes to do that type of stuff.”

“He plows. Maybe his plow guys weren’t there but he knows how to plow. He’s been doing it for many years,” the neighbor said.

“He’s a good guy. We don’t talk to him all the time but he’s nice. On the tough snow years, he did come by with his plow and asked people if they needed help.”

The neighbor noted that Renner “has got a lot of toys.”

“He’s got so many cars and trucks. On the street above us, there’s a wedding event center and there’s a bunch of cars parked. Those are his toys,” the neighbor said.

The neighbor, who’s lived several doors away for about 20 years, also said Renner tore down and replaced the house that was on the property because “people were staring into his home.”

“He values his privacy — that’s why he lives in the middle of nowhere,” the neighbor said.

The Washoe County Sheriff’s Office Major Accident Investigation Team is looking into the accident and Sheriff Darin Balaam is scheduled to hold a news conference at 3:30 p.m. local time Tuesday.

Renner — who calls Tahoe his “happy place” — often posts photos on social media from his home near the Mt. Rose-Ski Tahoe resort.

He told the Gazette-Journal in 2019 that he was drawn to the region by its majestic scenery, because Reno was the right-sized city for him and because it allowed him and his family to ski frequently.

With Post wires