Cooper, a Germantown Academy graduate, plays a bipolar former teacher who was released from a mental institution, moving in with his parents as he tries to get his life on track.
The Eagles, his parents, and an intriguing woman he meets are in the middle of his personal journey.
A lot of the film takes place in Delaware County in "a house that is very similar to my grandparents' house," said Cooper, adding that director David O. Russell "would have food being cooked in the kitchen so you would smell gravy throughout the day as you were working. All those things are really important. They actually help ground you. When you're making a movie, the goal is to be authentic. If we've succeeded at all in this movie, it's that you believe this group of people is a real family that lived in that house on that block in 2008."
Cooper said he had his uncle, Ernie Campano, spend some time with De Niro at the Four Seasons Hotel to help perfect his Philly accent for the movie.
Born in 1975, Cooper said his family's schedule revolved around the Eagles, the Phillies, and the 76ers.
"I remember the tail end of the Ron Jaworski [era] and then Randall Cunningham," he said. "And I was a huge Reggie White fan. I loved Donovan McNabb, and I was happy when Andy Reid came in."
Though he was only 5, he recalls watching the Eagles beat Dallas in the NFC championship game - "we brought the TV into the kitchen so we wouldn't miss anything" - which was only a few months after the Phillies won the 1980 World Series.
He reeled off a dozen Phillies he followed in the '80s and '90s, getting excited as he mentioned "Shake and Bake McBride and Michael Jack Schmidt" and remembering how he "used to keep score on the scorecard they had on the back of the Daily News." After they won the 1980 Series, "I remember my father taking me to see Tug McGraw at the Ford dealership to get his autograph."
Cooper, who became a megastar in The Hangover, says the challenging role he plays in Silver Linings Playbook is the best of his career.
"And to be able to do it in Philadelphia and have my cousins come over and have my mom there, it was special," Cooper said.
Contact Sam Carchidi at firstname.lastname@example.org. Follow on Twitter @BroadStBull.