Gia Coppola on directing her first film and working with James Franco

When your grandfather made the 'The Godfather', movies have to be in your blood. Gia Coppola tells Kaleem Aftab about her first film and which relative inspired her the most

Branching out: Gia Coppola

American cinema, it's a family business. Take the new film Palo Alto for example. It is directed by Gia Coppola, the latest branch of the Coppola family tree to step behind the camera and it stars Emma Roberts (niece of Julia) and Jack Kilmer (son of Val, who also has a cameo), whom Gia used to babysit. Small world when you run with the Hollywood elite.

Family connections also helped Coppola to meet James Franco, author of the short-story collection about angsty Californian high-school students on which her debut film is based: "I saw James in a deli one afternoon, and then I saw him again at a party that evening and someone introduced us", she says.

That someone was her mother, Jacqui de la Fontaine. Gia, now 27, never met her father, Gian-Carlo Coppola, as he died in a boating accident in 1986 while she was still in the womb. Born seven months later, she was named Giancarla after him, but called herself Gia as her American contemporaries struggled to pronounce the Italian longer form. There was no such thought about dropping the Coppola, as her relative Nicolas Cage did. "It's the name I was born with, it didn't even cross my mind to change it," she says. In 2000 her mother married Peter Getty, from whom she was famously, acrimoniously divorced 10 years later.

The first film from the granddaughter of Francis Ford Coppola suggests that she is more influenced by her aunt, Sofia's, work than that of The Godfather director. "She's like a big sister," she says. "My family and I are so close, it's important to have a close knit relationship and to make time to spend with each other, especially at the holidays."

She didn't even get to watch many of her grandfather's classics for a long time, because everyone on his Napa Valley winery where she was partly brought up had already seen them all, several times over. "I still haven't seen his first film, You're a Big Boy Now," she admits, seemingly oblivious to Dementia, the early film he made for Roger Corman, not to mention other lesser-known early efforts. She then adds, "He has a lot of secret films, which he made when he was younger that I want to get my hands on, such as short films that he made in college. He was always making something."

When Coppola met Franco, she had just completed a three-year photography degree at Bard College studying under the acclaimed photographer Stephen Shore. Upon finishing her course, at first she wanted to pursue another profession entirely. "I was working as a bar-back," she says in her lethargic Californian drawl. "You work and polish glasses for the bartenders and take out the trash. I wanted to be a bartender for a bit."

She would probably be quite good at it – she is personable and social, and responds to questions far more fully than the short ripostes favoured by her aunt, and bemoaned by so many interviewers. Was the decision to work in a bar an act of rebellion? "No. My family was very supportive of it. I was just unsure of what I wanted out of college and photography seemed stale. I wanted to do something completely different from what I was into, to see what I could get out of it."

She still keeps her hand in with the odd cocktail. "I make a little bit. I'm not very good at remembering recipes. I like making martinis because for Christmas my uncle [Roman Coppola] gave me a travelling martini case, so I can always be on hand when they want me to make one." As is the family tradition, Coppola had a wine named after her in 2012, cultivated on her grandfather's estate. She compares creating wine to making a movie: "There are all these different components you have to check on, the designing, the tasting, the marketing..."

Uncle Roman has been a help when it comes to movie-making, too. He appears in the credits for a number of Coppola's music videos and short films for fashion labels. It's in these short-form works that the influence of Sofia, and in particular her 2006 film Marie Antoinette, on her niece's aesthetic is clearest. Non Plus One, for the label Opening Ceremony, is typical – music-heavy, with a quirkily inventive narrative. A tribute to the French New Wave starring her uncle Jason Schwartzman and Kirsten Dunst, it begins in silence as Schwartzman returns home alone, and seemingly dreams up his dream girl. As she appears, a soundtrack of "Is This Sound Okay?" by Coconut Records kicks in.

As with her aunt's early films, in Palo Alto Coppola looks at the concerns of teenagers, primarily female, negotiating the move to adulthood. The major difference is that her characters want to engage with life, not wallow in ennui. "It's that sort of feeling of being young and aimless and trying to articulate your emotions", says Coppola. "There are so many hormones involved. Realising your parents are also human beings and that they are having their own issues and are not just these authority figures."

The protagonist is April (Emma Roberts), a teenage virgin who fancies her classmate Teddy (Jack Kilmer), though he is too awkward and hormonal to be a serious prospect. It is far easier to connect with her soccer teacher (James Franco) for whom she also babysits. Unusually for an American screen drama, April learns from her own mistakes in a realistic manner that avoids cliché and Gossip Girl-style melodrama.

As for choosing actors with famous parents, she says: "That didn't come into it. I picked the people who were right for the characters and not who is in their family." The key figure is Hollywood's James of all trades, Franco. Coppola showed some of her pictures to the actor after they met and he in turn sent her some proofs of his soon-to-be-published novel. She loved it and he had already decided that he wanted it to be a movie, although he didn't want to adapt it himself: "It's tricky to take a book of short stories and turn it into a feature film. I made it into an ensemble piece and James helped to make it as unintimidating as possible, starting off with the basics. He told me, 'Pick the stories that you like, just write interior / exterior and don't worry about dialogue, and we'll just go from there.'"

Franco became a mentor to her. She had grown up on movie sets but it was the actor who first took her to a film festival, Sundance in 2013. "James wanted to show me what it was like being at a film festival. It prepared me a little bit. Especially going with James. With him it's crazy. He was showing two films, we were there for two days and were up for 24 hours a day."

As for her own pace of life, she adds, "I can't move as fast as him as I get sleepy." She had better not rest up too long – the world is just waking up to the next Coppola to take Hollywood by storm.

'Palo Alto' plays at the Edinburgh Film Festival on 19 & 22 June (edfilmfest.org.uk), and East End Film Festival on 20 & 22 June (eastendfilmfestival.com). It will be on general release in the autumn