John Ratzenberger: Pixar perfect

John Ratzenberger explains to Tim Walker how he gave voice to a digital revolution after stepping down from the bar stool in Cheers

Budding actors are frequently advised to learn another trade, and if precedent is any guide, then carpentry makes a very good Plan B. Harrison Ford was building cabinets for George Lucas when the director cast him in American Graffiti. Thanks to Lucas's later films, Ford is now – judged by the box office receipts from his movies – the most successful actor of all time. The sixth name on the same list also belongs to a former carpenter, though his success has not earned him Ford's name recognition.

And yet this actor's films have collectively grossed over $3bn. He was in The Empire Strikes Back alongside Ford. He was in the first two Superman movies. He has worked with Ken Russell, Richard Attenborough, Milos Forman and John Schlesinger. And he's the only actor to have lent his larynx to a character in every single one of Pixar's 11 films – including the forthcoming Toy Story 3. You probably know John Ratzenberger best as Cliff, the bar bore from one of the most successful sitcoms of the Eighties, Cheers. "When I think back on all the historical events I was involved with without realising it at the time," says Ratzenberger, now 62, "it takes my breath away how fortunate I've been."

Ratzenberger grew up in a factory town in Connecticut where, he recalls, "family vacations for us meant going out in the back yard." In 1969, while he was doing some casual building work in Bearsville, New York, he heard that there was a large outdoor concert taking place nearby, whose organisers needed some heavy lifting done. Ratzenberger signed up to drive a tractor ferrying supplies around the site at, yes, Woodstock.

A couple of years later, he was in Britain to visit a friend in London. He planned to spend three weeks here, but ended up staying for a decade. During that time he established his own improv comedy troupe, Sal's Meat Market, and acted in 28 films, including Attenborough's A Bridge Too Far. On his return to the US, he soon picked up his role as ego-crazed mailman Cliff Clavin in Cheers. "Cliff was my baby," he says. "I auditioned for the part that became Norm, but I invented the character of Cliff during my audition instead."

Not many actors get to experience the collegiate atmosphere of a lengthy working relationship with a single team. Ratzenberger has had that joy at least twice, with both Cheers and Pixar. "And what unites them both," he explains, "is the quality of the writing. In Cheers you could never see the joke coming. Most other sitcoms you see it coming from five minutes away. If they weren't happy, the Cheers writers would change the entire ending of an episode while we were filming. Pixar are perfectionists as well – they'll work three or four years on a story before they start animating it."

Cheers and Pixar also share at least one other similarity – the artists are in control. On the former, says Ratzenberger, "They wouldn't allow any studio executive into the writers' room. There was a piece of tape in the hallway outside and if any studio exec crossed it the writers would just get up and walk out. The studio understood that the writers were sacrosanct."

Pixar's boss, meanwhile, is the director John Lasseter, and Ratzenberger describes the studio's headquarters with delight: creatives are allowed to work in offices of their own design, hence one has built his cubicle entirely from cardboard boxes, and another works in a tipi. "John's office is full of toys. It's like going into a big playground, but look at what they achieve at the other end of that. When I started at Pixar it was six people. Now it's a huge studio that took over Disney's animation. One of the beautiful ironies is that when he worked for Disney, John kept talking to his bosses about computer animation and they showed him the door. Now he's back and running the place."

Ratzenberger had never heard of Pixar when he was asked to voice Hamm the piggy bank in 1995's Toy Story. But by the time they asked him to take a cameo in their second film, A Bug's Life (1998), everyone knew about Hollywood's hottest animation team. P T Flea, the circus ringmaster in that movie, remains Ratzenberger's favourite Pixar role, "because everything in his life is a crisis – he always makes me laugh." Before the recently Oscar-nominated Up was released, Ratzenberger was ranked number 11 in the chart of highest-grossing actors. He's now up to number six – so Harrison Ford ought to watch his back when Toy Story 3 emerges in July.

Nowadays the studio writes roles to suit Ratzenberger. His part in Up was as a construction worker, and they cast him as Mack the truck in Cars, he explains, because his father was a truck driver and drove a Mack truck. His working-class heritage is reflected in his life outside the movies: he co-founded the Nuts, Bolts & Thingamajigs Foundation to encourage young people to learn a trade.

"Because I grew up in a factory town, I understand the value of being able to put a nut and a bolt together. The rest of us can't do what we do otherwise. If you're a surgeon, you'd better have a good plumber around, because if there's no hot water coming out of the tap, you're not doing any surgery. We're running out of skilled workers in the US and the same is happening here in the UK. So we started running camps to teach kids those skills. Hollywood has taught people that if you're a carpenter or a plumber or an electrician then you must be stupid. I wanted to give some respect to people who actually make something for a living."

That's not to say he doesn't admire Pixar's work ethic. "Until Finding Nemo," he says, "it was impossible to animate water and have it look like water. That was the chore they gave themselves. In The Incredibles, they'd never had fabric blow in the wind properly, so they set out to do that. The fur in Monsters, Inc was new. Every one of their films breaks a barrier. They could've rested on their laurels by now, but they never will. They view each film as if it's their first. That's why they're Pixar."

'Up' is available now on Disney Blu-ray, Disney DVD and Disney Combi pack