Joseph Gordon-Levitt: In the loop with Hollywood's next great leading man

Joseph Gordon-Levitt is having a terrific year, which seems strange to say when the past few have already seen him headline an adored indie romance (500 Days of Summer), lend bulk to a franchise tentpole (GI Joe: The Rise of Cobra) and bask in the glow of Christopher Nolan's Inception. Nonetheless, a second stint with Nolan in The Dark Knight Rises followed by this month's thriller double-bill, Premium Rush and Looper, and a year that will culminate in the release of Steven Spielberg's Lincoln, is further burnishing Gordon-Levitt's claim as the boy most likely to become Hollywood's next great leading man.

God knows the industry needs someone like Gordon-Levitt to step up as his generation's DiCaprio, especially since no one else appears able. Entering a Toronto hotel room with a bottle of water in his hands and a gentle swagger in his step, he has the appearance of a man very comfortable with his place in the universe right now. "How you doin'?" drawls the 31-year-old Los Angeleno, like he's suddenly been inhabited by the spirit of Joey Tribbiani. Looper opened the Toronto International Film Festival the night before and, before the onslaught of Cloud Atlas, Argo and The Master, he's getting the chance to be toast of the town. Looper, a funky time-travel thriller, reunites Gordon-Levitt with his Brick director Rian Johnson for what he describes as "a sci-fi movie that doesn't focus on shiny spaceships or lasers, but is ultimately more of a drama – much like The Dark Knight Rises."

Gordon-Levitt plays Joe, a mob assassin called a "looper" who targets agents zapped back from the future. Not a bad gig, until the mob decides to close your loop and dispatch your future self to be terminated. Unfortunately for Joe, the 30-years-older version of himself, played by Bruce Willis, escapes, forcing Joe to hunt him down and (maybe) finish the job. In no one's eyes do Willis and Gordon-Levitt look like each other, and the older man's casting led to a face-full of prosthetics for the younger in order to bring their features closer in line. Distractingly for Looper, the glue-and-rubber job also makes Gordon-Levitt resemble a lost villain from Warren Beatty's Dick Tracy.

"It's a bizarre experience to look in the mirror and see a face other than my own," muses the actor, who insists that the hours in the make-up chair he endured each morning were necessary to achieve his performance. Even Emily Blunt tells us later that when she first encountered her co-star on set, no one told her he was caked in prosthetics. "I was just really confused why he looked so different," she says. "I thought, 'What's he done to his face?' I thought he'd had an allergic reaction to a bee sting or something." The actress hastily adds, "It's a credit to his talents that he was able to embody Bruce Willis without cheaply impersonating him. They look nothing alike, but that's why you buy it – because of Joe."

The opportunity to work again with Johnson was Gordon-Levitt's chief motive for doing Looper. The film's essential theme is the cycle of violence and whether raising children in the right way can prevent them growing up to become fearsome psychopaths, as in the case of a dark-eyed child (played brilliantly by Pierce Gagnon).

"How a child is raised by their parents is, of course, going to have a profound effect on that child," he says. "Personally, I can vouch that my parents did an excellent job."

'Looper' is released in the UK on 28 September