As Emilio Estevez arrives for our interview, I am instantly reminded of a song: Simple Minds' Don't You Forget About Me. The quintessential Eighties tune written for that most quintessential of Eighties Hollywood teen films, The Breakfast Club, it sounds now like a hymn to the lost souls once known as the Brat Pack. A rather derogatory term coined for a generation of actors, Estevez was one of the ringleaders - together with his Breakfast Club co-stars, Molly Ringwald, Judd Nelson, Anthony Michael Hall and Ally Sheedy. They were the Lindsay Lohans and Ashton Kutchers of their day: young, rich and - according to some - arrogant.

Seating himself at a table overlooking a hotel beachfront, Estevez is initially reluctant to reflect on times past and takes some prodding. "We were portrayed as a bunch of young men and women who were interested only in money who used our positions as actors to further ourselves in ways that were unsavoury. But that wasn't true. We were hard working."

True or not, it wasn't enough. While some on the periphery of the Pack - not least Tom Cruise, Matt Dillon and Sean Penn - survived and flourished, most were consigned to a fate worse than Saturday morning detention: TV movie hell. Those who once expressed the hopes and fears of their peers in St Elmo's Fire, had their own expectations well and truly doused; most never recovered.

It's not hard to imagine Estevez humming along to Simple Minds' anthem even then. "This is a very fickle business and a very unforgiving business," he sighs, bringing a halt to his rapid chatter. "It's about who's on the cover of magazines, and what's current. And that's fine - that's the way it always has been. It's nothing new. But the older you get, whether you're male or female, it forces you to reinvent yourself."

As it happens, time has been kind to the 44- year-old. He is a little thicker around the neck and waistline than when he played wrestling jock' Andrew Clark in The Breakfast Club, but otherwise, he is instantly recognisable. The expectant blue eyes, the tufts of straw-brown hair and that sub-Cruise smile are all present and correct.

One thing is certain: Estevez was always ambitious. One newspaper article from 1986 claimed, "It's predicted he will be a Hollywood production czar within 10 years". Partly because he belonged to an acting dynasty headed up by his father, Martin Sheen, it wasn't as ludicrous as it sounded. That year, Estevez, then just 24, had written, directed and starred in Wisdom, a Bonnie and Clyde style caper with another Brat Pack alumni Demi Moore. Taking "a beating from critics" (one review dubbed it Bonnie and Clunk'), Estevez's film may not have ranked him alongside other actor-auteurs such as Orson Welles or Woody Allen, but it stated one thing: he wanted a career on his terms.

"For me, I think was unfairly depicted as a guy who was out partying all the time," he says. "But I wasn't. I was writing. For better or worse, I was home thinking about where I was going to be in 20 years." Sure enough, via a path that's taken him to the brink of obscurity, bankruptcy and depression, Estevez has finally got where he wants to be. When we meet, it's at the Venice Film Festival, where a work in progress' cut of Bobby - his fifth film as director - has just screened. This month, he will attend the Golden Globes, where the film will compete in the Best Picture category against such prestigious titles as The Departed and The Queen.

It rather justifies his own motto: expect nothing and be pleasantly surprised. Yet it is the viewer, particularly one who has followed Estevez's directorial career, who will remain surprised. Set in and around the Ambassador Hotel, Los Angeles, on the day Bobby Kennedy was assassinated, this complex Altman-like tapestry featuring a galaxy of Hollywood stars is so far removed from his previous work it defies belief. Not that there's much to go on. In 1990, he made his sophomore effort, execrable dustman comedy Men At Work, another self-penned effort in which he starred with his brother Charlie Sheen. The pair would reunite a decade later for Estevez's equally lamentable Rated X, the story of Jim and Artie Mitchell, who went from owning strip bars to becoming a major force in pornography.

By this point, his Brat Pack star had long since waned. He had stretched his career to the limits, resorting to starring in feeble sequels of films that barely merited them in the first place. The 1988 western Young Guns, where he joined the likes of Roy Rogers and Paul Newman in being another actor to play Billy the Kid, at least had the good grace to get it over and done with swiftly, spawning its follow-up two years later. As for 1987 comedy thriller Stakeout, in which he played a straight-arrow detective in an attempt to make the transition to adult star, it took six years to produce Another Stakeout. By this point, Estevez had been reduced to starring in The Mighty Ducks, a little league baseball story in which he played the coach, in a move that put his decline on a par with John Travolta's.

At the time, there was one last throw of the dice. In 1996, Estevez directed his father in Vietnam veteran saga, The War At Home. Based on the play by James Duff, Estevez played a soldier who returns to the US to find that he's still haunted by the conflict. To raise the $3 million budget, Estevez agreed to demean himself by appearing for free in Disney's D3: The Mighty Ducks, the third in the series, but while the deal was upheld, the company offered his own film paltry distribution. "That was a heartbreak," he admits. "It was so enormous that I wanted to quit. Sometimes the valleys that you go through, that you have to ride out, are so painful The War At Home, I thought was a terrific film and I love it. It was a small movie, and I worked on it for four years to get it made, and no one saw it!"

Between then and Rated X, he barely worked at all. It was during this bleak period that he began to toy with the idea for Bobby, but after writing 30 pages, he got "the worst case of writer's block that I had ever had. I was paralysed," he says. "It had reached a level that incapacitated me. People would ask me: What are you working on?' And I would say, I'm working on Bobby.' And yet I wasn't. Of course, I knew how it ended - we all knew how it ended - but I didn't know how to get there. As a result I shut down. I shut down as a writer, I shut down emotionally, I froze." A black cloud of depression set over his head. "I think everyone was concerned about me. I wasn't working - I had withdrawn and I was very isolated."

In the end, he had his brother Charlie to thank. Sheen, who began his acting career in such Oscar-bedecked films as Platoon and Wall Street, had similarly hit the skids after he was forced to testify in the infamous case of Hollywood madam' Heidi Fleiss. But while these siblings were once bitter rivals - Estevez even reputedly said, "Everything came easy for him, he didn't have to work for the things my parents made me work for" - their bond had stood the test of time.

"Charlie came to the house and he said, Can I read those 30 pages?' I think they his family all believed they didn't exist. And so, he took the pages into the backyard, and read them and I watched him through the window and I can tell he's involved and engaged. He comes back inside and says, You must finish this.'"

The next day, Estevez packed up his car and drove north of Los Angeles, to the sleepy town of Pismo Beach, near Santa Barbara. He pulled into a motel and experienced a remarkable coincidence the building's receptionist, Diane, was present in the ballroom at the Ambassador the day Kennedy died. "She was the muse, the inspiration, the intervention, that allowed me to continue," says Estevez. "She was a youthful Kennedy volunteer and had spent the day canvassing for Bobby, knocking on doors. She came back to the hotel, for the celebration, and heard the shots. The way she described it was so accurate; she said it was as if the rug was pulled out from her entire generation."

Estevez was six years old when Kennedy died, on June 5, 1968, but it made a profound impact on him. He can remember going into his parents' bedroom - they were vacationing at his mother's parents' house in Ohio - and waking them to tell them the tragic news. A few months later, his father - who had met Kennedy in his time - took him to the Ambassador Hotel to pay homage to the man. "I didn't set out to make a political statement," notes Estevez now. "But I've made a movie about a guy who was inspirational not only to me, but to an entire nation - and perhaps the whole world. He does remain the greatest What if?' in the history of American politics."

But while Estevez sees the film as a tribute to an inspirational man, it has not been widely embraced in the US. Despite the fact it's the first major film to focus on Bobby Kennedy, mixed reviews have meant a stuttering box-office total that barely hit $10 million. Perhaps it's that Estevez's film - unlike Oliver Stone's JFK, about the murder of Kennedy's presidential sibling in 1963 - eschews the conspiracy theories surrounding his death. A recent Newsnight investigation by Shane O'Sullivan claimed there was evidence that three CIA agents were involved in the murder, rather than 24-year-old Palestinian Sirhan Sirhan, who was arrested as the lone assassin.

This lack of willingness to question events might be why the Kennedy family has embraced the film - writing a letter to Estevez and Harvey Weinstein (whose company distributed the film) for their sensitivity. According to Estevez, he sets out to paint a fictional portrait of "regular folks" who just happen to be in the hotel that day, even comparing Bobby to the disaster movies of the Seventies, like The Poseidon Adventure.

"It's a disaster movie on an emotional scale," he says. "It's the disaster of the heart. It's about the death of decency, and the death of innocence and hope in America." Featuring a cast that includes Anthony Hopkins, Demi Moore, Sharon Stone, Elijah Wood, Laurence Fishburne, Lindsay Lohan, Heather Graham, Ashton Kutcher and Christian Slater, who all play various guests and hotel employees, the most important role - of Kennedy himself - is not cast, with archive footage used.

There's even room for a Brat Pack reunion in the shape of Estevez and Demi Moore, who were once engaged for a time. In Bobby they play a married couple - Moore's alcoholic club singer Virginia Fallon to Estevez's put-upon husband.

"I haven't acted in a movie for a long time and it took a while to get my confidence back," Estevez admits. "I didn't fully feel confident until the last day of shooting."

There's something remarkably humble about Estevez now. While his father, who makes an appearance in the film as a depressed stockbroker, once dubbed him "scrappy and cocky", this seems to have given way. "He's the most compassionate man now," says Sheen. "He is so respectful of actors. If you've never been on the set with him before, you would be astonished at how kind he is to everyone."

Performing, of course, is in his blood. Aside from Charlie, younger brother Ramon and sister Rene both act. Born in New York, where he lived on the Upper West Side of Manhattan until his family relocated to Malibu in 1968, Estevez grew up with the likes of Chris and Sean Penn and Rob and Chad Lowe as neighbours. At the age of 14, he was on the set of his father's finest hour, Apocalypse Now, though his role as a messenger boy was cut out. He was even starting his career as a director from a tender age. "Charlie and I had a little 8mm camera, and we would make movies in the backyard," he recalls, "so whoever wasn't on camera was directing."

Switched to the family name of Estevez because he didn't want to ride on the coat-tails of his father's success, by the time he was 20 he had appeared in Brat-Pack blueprint The Outsiders before gaining cult status for his work in 1984's Repo Man. After The Breakfast Club and St Elmo's Fire, his fame increased rapidly, though he maintains being a celebrity was less of a trial then.

"It wasn't as it is today. In the Eighties, you didn't have the internet and you had limited access. Now it's all access all the time. When George Bush says, We're bingeing on oil', I think we're bingeing on gossip."

Even so, Estevez suffered at the hands of the media. Just as his engagement to Demi Moore hit the dirt, a story circulated that model Carey Salley claimed he was the father of her son Taylor and daughter Paloma. She sought £10,000 a month in child support, and court records showed that although Estevez never acknowledged the children, he was paying her £2000 a month. The childcare was left to his father, who not only videotaped Paloma's birth but also arranged Taylor's baptism. At the time, Estevez was a Catholic, though it seems he still doesn't seem eye-to-eye with his father on that one. "I'm more agnostic. My father desperately wants me to practise Catholicism and I'm not there yet. Maybe in ten years, when I get a little older and feel a little bit older!"

At least he shaped up to be a responsible father, eventually breaking his silence in the press about his paternity issues. "I've got two extraordinary children," he says. "My son is 22, my daughter is 20. They're functioning human beings in the world and so that was part of my life's work."

The voice of a concerned parent certainly shines through when Estevez speaks about politics in relation to Bobby. The film brims with idealistic youthful characters that fight for their beliefs in a way he believes that today's teenagers are no longer inspired do. "Young people need to re-engage in the political process in America," he says. "There is such apathy now. Young people are disenfranchised. What we're lacking right now is true leadership."

These days, he lives on his property in Malibu, where he spends his time cultivating a small vineyard, which produces 100 cases of pinot noir a year. "Friday afternoon, I'm picking the bugs off the tomatoes and now I'm here," he shrugs, hardly able to believe it. He lives there with his fiance, Macedonian journalist, Sonja Magdevski, who "has no interest in acting" but got a walk-on in Bobby when Estevez's sister had to pull out. It promises to be a sounder relationship than his previous union to former pop diva Paula Abdul whom he wed in 1992, only to split two years later. "A high-profile marriage, high-profile divorce, that really cost me," he says with a grimace.

Living testament to the fact that such a lifestyle can be damaging, Estevez's new existence outside of Hollywood has evidently seen him through the lean times. With a bit-part voiceover in next month's kids' movie Arthur And The Invisibles, how does he feel if the film re-ignites his acting career?

"If it does, great," he says. "Everything is interconnected with this. If you're known for something, then you're known for something else. Actor-director. I'm a hyphenate now and it's chic to be a hyphenate, I'm told." Whatever happens, he can rest in the knowledge that we didn't forget about him. The PR comes over to wind the interview up. "That's it?" he cries.

"I was just getting started."

Bobby opens on January 26