She owned the 1990s... but then she disappeared (due in no small part to that unfortunate shoplifting incident). Now, Ms Ryder is back with quite the bang in her latest role, as the wife of a notorious real-life Mob hitman.

It seems like only yesterday that Ryder was a fresh-faced not-so-innocent in 1988's coming-of-age black comedy Heathers. Twenty-five years on, she is still tiny and fragile-looking, but as she points out, "I feel a little stronger than people perceive me."

Today, we're sitting in a windowless marquee at the Venice Film Festival. A noisy portable air-con unit is doing it's best to keep us cool. "Am I over-heating?" Ryder asks. "Or is it really hot?" It's hot, I assure her, though she couldn't look cooler if she tried. Which seems appropriate, given her new film is The Iceman, a true-life tale of New Jersey hitman Richard Kuklinski. Ryder, as his wife, delivers her best work in years.

Maybe the film's deadly subject matter is why she's arrived for our interview in funereal black – Christian Louboutin heels and a short-sleeved, knee-length dress. It was once worn by Audrey Hepburn to a screen test, she explains, with a quiver of embarrassment. "Back in the early 1990s, they'd have auctions at the studio." She has a collection of vintage Hollywood outfits, apparently, including Leslie Caron's dress from An American in Paris, Claudette Colbert's gown from It Happened One Night and Olivia de Havilland's blouse from Gone with the Wind.

"What you wear – and it always starts with your shoes – determines what kind of character you are," she explains. "A woman who wears high heels carries herself very different to a girl who wears sneakers or sandals. It really helps determine how you carry yourself."

Quite what Ryder's outfit says about her today one can only speculate; like Hepburn, you can certainly make the case that she remains one of the defining Hollywood stars of her era. In the same year as Heathers, aged just 17, she starred in Tim Burton's Beetlejuice; within five years, she'd taken roles for Francis Ford Coppola (Dracula) and Martin Scorsese (The Age of Innocence). Two Oscar nominations came in quick succession – for Scorsese's Edith Wharton adaptation and, a year later, for Little Women.

While she lost out both times – to Anna Paquin and Jessica Lange respectively – it hardly mattered. Emerging as a poster girl for Generation X-ers after starring in slacker touchstone Reality Bites – she even dated musician Dave Pirner, of Soul Asylum fame for a time – she then teamed up with Al Pacino for Shakespeare doc Looking for Richard and starred opposite Daniel Day Lewis in a film adaptation of Arthur Miller's The Crucible. She capped the decade by producing and starring in Girl, Interrupted, a moving adaptation of Susanna Kaysen's memoir about her stay in a mental institution.

But if the 1990s belonged to her, it's fair to say the following decade did not. In 2001, Ryder was arrested on shoplifting charges in Beverly Hills, accused of stealing $5,500 worth of designer clothes and accessories from a department store. Three years' probation, 480 hours of community service and counselling followed. Even her signature on a petition to pressure the Bush administration to sign the Kyoto agreement on climate change was refused because she was a convicted felon.

Ryder, who had already seen the demise of a two-year relationship with Matt Damon, disappeared from public view, though it wasn't the first time. After 1997's Alien: Resurrection, she didn't work for two years – "a conscious choice" – because she didn't read any scripts she liked. This was different, though; Ryder, the wounded bird, hibernating. "I'm not big on the internet," she tells me at one point, and you can understand why; too much exposure to cruel jibes. As she once said, "We're sickeningly well-paid people who have charmed lives. But that doesn't mean you don't have problems."

Still, as everyone knows, Hollywood loves a comeback; just look at Robert Downey Jr – who, thanks to the success of Iron Man, appears almost impregnable now. Back in 2003, Woody Allen had wanted to cast both Downey and Ryder in Melinda and Melinda – Ryder had worked with him once before in Celebrity – but, as he told one reporter, "I couldn't get insurance on them." Three years later, however, Ryder and Downey finally did get to work together – along with Keanu Reeves, Ryder's co-star from Dracula – in Richard Linklater's animated take on Philip K Dick's A Scanner Darkly.

It was the first in a series of baby-steps taken to resurrect her career. She was particularly wonderful in Darren Aronofsky's Black Swan, as the embittered, ageing ballerina. "The script was so interesting, and kinda weird," she notes. "It's one of those movies where you go, 'Is this gonna work?' because it's about the ballet world and she's hallucinating and all this stuff. And then it worked! When I saw it, I was blown away."

There were more small but significant roles, in Rebecca Miller's The Private Lives of Pippa Lee, Ron Howard's domestic comedy The Dilemma and JJ Abrams' Star Trek, playing k Spock's mother. She also reunited with her "dearest" Tim Burton – 22 years after Edward Scissorhands – to voice a role in last year's animated Frankenweenie. "I credit him so much with my career in a way," she says, referring back to Beetlejuice. "It wasn't my first movie. But it was a movie that was really important to me."

The Iceman is a further step on her path to becoming reacquainted with Hollywood. As Deborah Pellicotti, the unsuspecting suburban spouse to the film's titular hitman, played by a volatile Michael Shannon, it's a frank reminder of how powerful Ryder can be. "I've never played a person who existed without their blessing and them being there on the set," she says. "I had to get used to that." It so happens that the real Deborah – actually named Barbara Kuklinski – was involved in a rival movie project with Mickey Rourke, which ultimately fell apart.

While the film graphically details Kuklinski's working methods – he is said to have killed more than 100 people for the Mob – the big question that looms over the film is whether Deborah/Barbara really knew about her husband's crimes. In a recent interview, Barbara Kuklinski claimed she was furious when she heard that Ryder had said that she was as guilty as her husband, who died in prison in 2006. In fact, the actress does not attribute blame, but seems utterly intrigued by "the ambiguity" that this story throws up, dramatically speaking.

She speculates that it's possible Barbara was in a state of denial. "I know a lot of people who have been married for a long time and they find out there is another woman or another man or the person's really an alcoholic or drug addict. And they genuinely had no idea. I think with her, it would mean having to acknowledge and take responsibility for herself."

Again, it makes you wonder about Ryder; she's been engaged twice – to Depp and Damon – but never married. Is this why she's never wed? A trust issue? "No, no," she says, shyly (she told one interviewer that she is a "strong believer" in marriage, given her parents are still together after 40 years).

She swiftly steers the conversation back to the film. "I hope the movie brings this up – there's sort of a denial in society… maybe I was drawn to it because I honestly don't know. I really don't know what she knew. I really wanted to play with that."

Whether The Iceman will help Ryder re-establish herself as a major force remains to be seen. She seems hopeful, at any rate. "I definitely count my blessings," she nods. "I feel like I've had such a great ride. Early on, to be able to work with some of the people I did, I feel really lucky. There is this thing, certainly in America, of women fearing getting older. Or people trying to make you think it's a really bad thing. I'm the opposite. I enjoy getting older. I'm 41 now. And I was so psyched on my birthday."

Why? "I feel like you get better. It's just a weird thing that I've never understood," she adds. "I do think it comes from… when I was younger I wanted to be older, I wanted to be with older people, but I was always too young."

Her desire to be around adults as a youth comes as little surprise. Born in Minnesota – and named after the city of Winona – Ryder grew up surrounded by adults, fascinating and inspirational figures. Her parents were products of the 1960s countercultural elite; her father, the author Michael Horowitz, hobnobbed with Beat icon Allen Ginsberg and was an early acolyte of LSD guru Timothy Leary, Ryder's godfather. Horowitz was also a big fan of the musician Mitch Ryder, the inspiration for his daughter's stage-name.

Does she remember being around such influential characters? "Well, I was a little kid," she says, before offering up an anecdote about a photo of her, as a three-year-old, on the shoulders of Lawrence Ferlinghetti, the American activist and author who also published Ginsberg's infamous poem "Howl".

"As far as Timothy [Leary] goes, I've said this before, he was my godfather and that's what he did: he took me to ball games, he made me do my homework; I was never exposed to any weird drug. It was very, very protective, and very fun. And I had a genuine great love [for him]."

She stops, faintly embarrassed again, unwilling to probe too deeply into cherished childhood memories. Then something comes to her. "I do remember... this was a big bummer for me. I was once told that I was playing, and John Lennon was there. I was too young to know [who he was]. I got in trouble because I gave something to [his son] Sean. I get told all these amazing stories, but at that time, they were just grown-ups. Now I'm older, I'm like, 'What!?' Because now I have the appreciation."

Mostly raised in San Francisco, Ryder spent part of her childhood on a commune called Rainbow in northern California, living with seven other families. With no electricity or television sets, she was first exposed to movies when her mother screened some in the family barn. Whenever she went to the city, she'd spend a lot of time at City Lights, Ferlinghetti's landmark bookstore that had become widely known during the 1957 "Howl" obscenity trial. "It's a really special place," she says, noting that it fostered a love of literature from an early age, inspiring her to collect rare first editions from authors such as Jane Austen and George Orwell.

With her father an atheist and her mother a Buddhist, Ryder's upbringing wasn't all smooth. She was bullied at school when she was 12, beaten up and called "faggot" by a group of kids who thought she was a boy. She was then homeschooled until enrolling, the same year, at San Francisco's American Conservatory Theater, where she took her first acting lessons.

While some of the adults around her may have dabbled in drugs, she had no interest. "My parents really did me a solid [favour] by taking all of the mystery of that stuff for me. So I was really like, 'I don't want to!' For a lot of my friends, it was forbidden so they wanted to do it all the time. I remember being told if you want to try it and experiment, go to an adult, don't get it on the street. I never wanted to because they were telling me exactly everything about it, that you could freak out in a crowd, in a concert."

Certainly Ryder doesn't appear so entrenched in Beat culture; when the topic of the recent movie adaptation of Jack Kerouac's On the Road comes up, she seems unaware of its existence. That's what staying off the internet will do for you. If it suggests Ryder is out of the loop, it can only be a temporary situation for an actress who has started to find her feet again with baby-steps that will soon become strides.

In the can is a sci-fi thriller with Antonio Banderas called Autómata, and a crime story, Homefront, written by Sylvester Stallone and set in the world of crystal-meth dealers. Ryder plays "a very tough, hardened ex-biker" involved in setting up the meth labs. She seems delighted; if anything will dissolve that fragile-bird image, it'll be roles like this. "It is very different from anything I've done," she smiles. "It's a very unexpected script." Unexpected – it's a word that seems to suit Ryder. That and "forever".

Independent News Service