Bradley Cooper: The Hangover's blue-eyed boy gets serious with film about mental illness

He's best known as a lager-swilling frat-boy, but his next role, as a bipolar teacher, is set to win Bradley Cooper awards. Matt Mueller meets him

Winner of the Audience Award at the Toronto International Film Festival, the accolade that propelled The King's Speech and Slumdog Millionaire onto their prize-gathering trajectories, and warmly embraced at the London Film Festival, Silver Linings Playbook is already quite the crowd-pleaser.

But while writer-director David O Russell, Jennifer Lawrence and Robert De Niro bask in its glow, no one is likely to gain more career upside from the film than Bradley Cooper. The Hangover's blue-eyed breakout gets to show off dimensions we're not used to seeing as an unbalanced high-school teacher who moves back into his parents' Philadelphia home following court-ordered confinement in a psychiatric hospital. He grounds the film, allowing De Niro and Lawrence the flashier moments as his OCD father and the damaged young widow he falls for, while supplying a few fireworks of his own.

"It's a very delicate balance one has to create to be the audience's chaperone for this film," says Cooper, 37. "We realised that early on in terms of modulating Pat's mental illness." The film-maker and star experimented with a more overt portrayal of Pat Solitano's bipolar disorder, dabbling with Asperger's before opting to pull back. "As David said, 'Mental illnesses are like snowflakes: no two are the same.' Pat's trigger is that a traumatic event can send him off into a hysterical state; other than that, we decided he would be functional, only without a [social] filter."

Cooper admits he was trepidatious when he first read Russell's script, unsure after his post-Hangover penchant for disposable Hollywood fare like The A-Team and Limitless whether he had the necessary chops to play Pat. "I made the leap because David believed in me and then it ended up being one of the easier experiences I've had playing a role," he explains, "I don't know what that says about me..."

Cooper wasn't Russell's first choice; that would have been the star of his last film The Fighter, Mark Wahlberg. When Wahlberg couldn't reach a deal with executive producer Harvey Weinstein, Russell found himself drawn to native Philadelphian Cooper, thanks to his bristling, shark-eyed turn as Rachel McAdams' fiancé in Wedding Crashers. "He was so palpably angry in that movie," the director expands, "so I knew he could play somebody intense. He told me how that anger was something he had hidden behind at that time, which I thought was interesting. This was an opportunity to show off another dimension of Bradley. His character does the same thing in the film. He's saying, 'You don't know me, but I would like you to know me'."

Silver Linings Playbook is set in and around an Italian-American neighbourhood in Philly that is populated by a batch of neurotics, who are united by two obsessions – home-made Italian food and football. Shooting in the suburb beside the one where he grew up helped Cooper to settle his nerves. "It was very soothing and familiar to me," he says.

Reuniting with his Limitless co-star also helped. Cooper describes De Niro as his "anchor", even though the two spend much of the film in a stand-off. He won't be drawn on similarities between his bond with his on-screen father and real-life father, Charles, who died of cancer last year. It's a relationship he once described as "complicated". Today, he'll only say, "Anything in my life is up for grabs when I'm looking for inspiration, that's the way I see it." He did, though, lobby, unsuccessfully, for his mother's maiden name, Campano, to be used as the family name in Silver Linings Playbook. And mirroring the closeness between Pat and his mum (Animal Kingdom's Jacki Weaver), Cooper moved his mother out to LA to live with him after his father's death.

"Pat is healed by his family, by love," says Cooper. "He's lucky enough to have people like that in his life, and I've been lucky in my life too to have a lot of love around me. So when anything bad happens, I can relate to the feeling that there's healing in your family."

Cooper's personal turmoil includes a partying past that got so out of control he decided to forsake alcohol when he was 29 – which certainly puts some distance between himself and the franchise that made him a star. "I wouldn't say it's easy not to drink but I just don't," says Cooper, who was briefly married to Jennifer Esposito, went out with Renée Zellweger and is currently dating Zoe Saldana.

One senses that, having shored up his position on Hollywood's A-list, Cooper would love to leave childish things behind. Would he mind if The Hangover ended up as his epitaph? "If that's the case, then I'm blessed for it", he says. "I'm proud of The Hangover." At the same time, he offers a rather sardonic assessment of the third film, which he's been filming between LA and Las Vegas since September: "Uh… another one," he mutters, before cracking up. He's getting $15m to play eternal frat-boy Phil again: is three times the limit? "I'd say so."

A graduate of Georgetown who wrote his college thesis on Lolita, Cooper also has an enduring love for The Elephant Man. He's identified with the deformed Joseph Merrick since his teens, apparently, and played him this summer at the Williamstown Theatre Festival in Massachusetts – a production he is now angling to bring to Broadway in spring 2014. "His story just moves me," he says. "The movie moved me when I was 12, the play moved me…" Cooper pauses. "I can't really explain it."

A collaboration with Derek Cianfrance and Ryan Gosling on their follow-up to Blue Valentine, The Place Beyond the Pines, demonstrates that smart film-makers are now finding new openings for Cooper's talents (somewhat surprisingly, Pines ends up belonging more to Cooper than it does to Gosling). He also pairs up again with Lawrence for Susanna Bier's Depression-era drama Serena, has been cast opposite Emma Stone in Cameron Crowe's next film, and will reteam with Russell for an ensemble piece about the 1980s Abscam scandal, when an FBI sting operation exposed several layers of Congressional corruption. Cooper will play Mel Weinberg, one of the conmen involved in the scam, opposite The Fighter's other headliners Amy Adams and Christian Bale. For the time being, he seems to have replaced Wahlberg in Russell's affections.

"There's a reason why we're doing another movie right away: We get along great and work well together," says Cooper. Before The Fighter, the controversial director's career had been bedevilled by starry misfires like I Heart Huckabees, toxic publicity (a rant at Lily Tomlin on the Huckabees' set became a YouTube hit) and misfortune (he had to abandon Nailed, a political comedy starring Jessica Biel and Jake Gyllenhaal, mid-shoot when financing collapsed). With Silver Linings, he finds himself back in the industry's good graces, and able to get the best out of People's Sexiest Man Alive, 2011, without the need for verbal abuse. "David pushes everybody but he always does it with love," insists Cooper. "A director can be strong and tough but if it's coming from a loving place, then I will do anything they ask."

'Silver Linings Playbook' is out on 21 November

This article will appear in the 17 November print edition of The Independent's Radar magazine