When Tina Fey was growing up in Philadelphia in the mid-1970s, aged five or six, her dad would let her and her brother stay up to watch late-night comedy. Mr Fey didn’t seem bothered by the lateness of the hour or the grown-up content — Fey remembers watching Monty Python, Mary Tyler Moore, George Burns, Carol Burnett, Rhoda, and Laverne & Shirley. The only parental controls were quality. He let his children watch the classic 1950s sitcom about domestic strife, The Honeymooners — “But not The Flintstones, because he thought that was a cheap rip-off of The Honeymooners,” she giggles.

What she remembers from that time, as she sits in her New York office during a break from a writer’s day on her hit sitcom 30 Rock, is how different female comedy parts were. “Mary Tyler Moore was a working woman whose story lines were not always about dating and men.” She seems slightly surprised at her own statement. “They were about work friendships and relationships, which is what I feel my adult life has mostly been about.”

So when Fey set about creating 30 Rock’s lead character, Liz Lemon — the head writer on a sketch show that tangentially resembles the US comedy institution Saturday Night Live — she thought back to those dark 1970s nights, snuggled on the couch laughing with her dad, and she set out a list of ground rules that, even as she desperately clarifies them later, underline one of the problems in comedy today.

“We wanted to make sure that everything we did with Liz Lemon rang true on some level — to me or to one of the other women in the room,” Fey explains. “And we did kind of know we were going into her as . . . well, as the opposite of a Sex and the City character. She’s not about wish fulfilment or fantasy. I personally am a big fan of SATC — but it’s pretty and it’s fun to watch, like candy. One is a fairy tale, and the other is a grim fairy tale.” She pauses, wonders if she’s been too rude, and rushes in with: “I do really enjoy Sex and the City in spite of what I just said.” Another pause. “I think I identify with Miranda. The redhead lawyer. I enjoyed her story lines most.”

When you flick through previous interviews with the new queen of comedy, it’s clear most journalists have worked out why she dodged the fairy tale and chose Miranda, the sharp-talking lawyer, as her favourite — it’s all about genetics. Fey’s dad has a German background, and her mum is of Greek stock. Hey, those crazy Greeks with their flapping hands, magazine opinion has it, crushed by the German genes, with their cold, ruthless streak. Fey’s career took her from performing live improv theatre in Chicago straight onto the writers’ table at Saturday Night Live, coming up with the smarts in the heart of Manhattan. She also lost a bit of weight and tidied up her hair once she arrived, a doggedly pursued process that has — seriously — been compared in print with Leni Riefenstahl’s makeover of the Third Reich. One writer described Fey as a “sprite with a Rommel battle plan”.

All of this is kind of hard to square with the cute, dark-haired, 5ft 4in but slim and toned woman with a sly grin and regular fits of giggles giving this interview. If this woman had made Triumph of the Will, she would probably have tickled the Ubermenschen as they stretched their arms forward until they dropped their pose and doubled up laughing. Fey is working on a project with Sacha Baron Cohen about a Jewish musician joining a punk band, and spent three months of 2008 ripping Sarah Palin to pieces with terrifyingly perfect impressions on SNL. Rommel? Not really.

It’s worth a brief aside on the Sarah Palin thing. Fey’s uncanny version of McCain’s running mate has been credited with everything from boosting 30 Rock’s ratings, and thus saving it, to gaining her recognition outside the hardcore comedy crowd that has long adored her. (And maybe adored her a bit too much. On a recent junket, a journalist said he’d been watching 30 Rock nonstop on DVD, and there was something he needed to know: what was the import of the framed photo of the two thermostats sitting behind Liz Lemon’s desk? “Well,” said Fey, “that was put there by our very talented set dressers, and I guess it’s supposed to look like comic boobs.” “Oh . . . okay,” said the journalist, seemingly downcast. “I thought maybe there was some kind of a connection to you, and it had a hidden meaning.” “That one has — there’s just no hidden meaning there,” she consoled him. “It’s comedy boobs.”)

Certainly, via YouTube the Palin skits played out to millions around the world, all grimly fascinated by the appeal of a woman described by the right-wing shock jock Rush Limbaugh as: “Babies. Guns. Jesus. Hot damn!” It’s not something Fey is entirely comfortable with, however. This isn’t only down to her liberal politics — her parents were Republicans, but she was on the picket line during last year’s writers’ strike — it’s also to do with how she fought her way up.

“I had a great time doing it,” she explains carefully, “but it was one of the strangest things that’s ever happened to me. You can grow up thinking, ‘I want to be on SNL one day’ or ‘I want to be in a movie some day’, but you never think, ‘I hope there’s a politician who looks just like me.’ So much of everything I’ve ever done has come out of hard work and just hanging in there, being the last one standing at the bar — and then to have that fall in my lap was just crazy. Having done plays in Chicago for two actors and then all of a sudden people are just saying, ‘Yes! Put the outfit on! You can say whatever you want!’ ” And she almost shivers at the thought.

Because, whether it’s the Greek Parthenon-building genes or the German opera-writing genes or, who knows, growing up a bit dumpy at a high school full of sculpted cool kids, Fey has worked very hard to get where she is today. Consider the CV: 38 years old; movies such as Mean Girls ($130m at the box office) and Baby Mama ($64m) under her belt; head writer and face of the most successful comedy show in history; writer, producer and star of her own sitcom; five Emmy awards, three Golden Globes. All of it, to an extent, prompted by mean kids mocking her natural adolescent awkwardness. She used her brains and her wit and her drive to swim the shark-infested playground pool — no way is she going back to that “what you look like is what you are” agenda.

She recalls starting to use the funny stuff she’d been so avidly consuming at home as a weapon at school when she was about 12 or 13. “You start to try and use that as a way to draw attention away from just how greasy you are. And squat. It’s good deflection,” she shrugs. She was like Janis in Mean Girls: she didn’t run with the cool crowd, but she was sharp enough to keep the bullies off her back and avoid being plucked from the herd by scavengers. She was pretty sporty, but found an outlet for all those pent-up years of late-night comedy-watching in an anonymous column in the school newspaper, written as The Colonel. Mostly poking fun at students and staff, she sailed close to the wind with double entendres that sometimes became a little too single. “Anals of history”, for example, proved especially trying to the school establishment.

From there it was an uneasy drama degree at the University of Virginia, followed by a revelation when she joined Chicago’s The Second City improv troupe. “I studied the usual acting methods at college — Stanislavsky and whatnot,” she has said, “but none of it really clicked for me. At The Second City, I learnt that your focus should be entirely on your partner. Suddenly it all made sense.”

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