Gary Cooper’s daughter, Maria Cooper Janis, realized how fine an actor her father was while watching him film a scene from 1952’s High Noon. It wasn’t a dramatic speech or shoot-out that impressed her. It was the way Gary enthusiastically lifted up Grace Kelly, who played his bride, as they filmed a romantic scene.

“That morning, he had put his back out very painfully — and Grace wasn’t petite,” Maria tells Closer. “Sweat broke out on his upper lip from the pain, but he looked like the happy groom. I thought, ‘That’s a good actor.’”

Called “Coop” by his closest friends, this three-time Oscar winner made a career of playing heroes and inspiring everymen in films like Sergeant York, Pride of the Yankees and High Noon. These tough but fair-minded and honest men also reflected the person Gary wanted to be in his personal life.

“He always said he liked to portray the best a man can be,” says Maria, who will be celebrating her father’s life and work with a retrospective opening up later this month at the University of Southern California.

‘High Noon’ Actor Gary Cooper’s Only Daughter Maria Says Her Father Was ‘Very Nonjudgmental'

Born in Helena, Mont., in 1901, Gary grew up with a healthy respect for nature and other people. “A lot of his close friends were Native American kids. He learned a lot from them,” Maria says.

Meanwhile, his parents, who were emigrants from England, taught their son to be a gentleman. “I think his background was a mixture of a good education, discipline and being able to relate to nature,” Maria says.

Gary had already become a star in films like 1929’s The Virginian when he wed Maria’s mother, New York socialite Veronica “Rocky” Balfe.

Maria, an only child, arrived in 1937. “We did so many things together as a family,” she recalls. The Coopers enjoyed tennis and golf outings, visits to the beach, weekend barbecues and trips to Paris and London together.

“I was extraordinarily blessed,” Maria admits. Their family withstood tough times, too. In 1948, Gary fell hard for his The Fountainhead costar Patricia Neal, and he and Rocky separated.

“My mother was very wise,” notes Maria, who says that Rocky encouraged her to show kindness to her father when the news of his affair went public in 1951. “She said, ‘Your father is in the other room, and he’s very upset. Go give him a hug.’ I never had to take sides,” she says.

Gary returned home in 1953, and he and Rocky remained together until his death in 1961. “I think he regretted the lost time away from family life,” says Maria. “But he and my mother never lost respect for each other, and they never really fell out of love.”