Janeane Garofalo has been to Scotland once before when a former boyfriend appeared in Annie Griffin’s Glasgow-set comic-drama The Book Group in 2002. ‘It was a really beautiful place, but at the time, unfortunately, I had a bit of a drinking problem. I just drank way too much while I was there. For three whole weeks, I was drunk or hungover 90% of the time.’ Before the long-distance phone chat threatens to get too heavy, the witty Garofalo steps in. ‘I blended in beautifully.’

The 44-year-old comedian, actor, radio show host and campaigner for left-leaning liberal causes (she recently got into a bit of bother for accusing tax protestors in Boston of being ‘racists’ whose actions were in fact about ‘hating a black man in the White House’) has been clean and sober for several years now and is looking forward to experiencing Edinburgh through fresh eyes. She’s also been encouraged by the fact that her alt-showbiz pals (Henry Rollins, Kristen Schaal, Eugene Mirman for three) have long urged her to make the trip. ‘There have been nothing but glowing reports about Edinburgh, but until this point, I’ve just had other things in conflict for me to be able to do it.’

For those who are not out-and-out fans, Janeane Garofalo has the kind of face you simply feel you know, but can’t quite place. Had you been awake throughout the 90s, you might have seen her on big screens in indie hits The Truth About Cats and Dogs and Reality Bites, while on TV, she appeared on Seinfeld for two critical episodes as the female equivalent of Jerry, before that plum role finally came along as the acerbic front-of-houser Paula in spoof chat programme The Larry Sanders Show. From that point on, when US casting agents were looking for someone to do ‘acerbic’, Garofalo must have fitted the bill every time. She also does ‘prickly’ and ‘attitude’ having offered that in buckets as Louise Thornton in The West Wing, the show which she is most proud to have made.

TV-wise, Garofalo hankers a couple of regrets: that she appeared as herself alongside Sandra Bernhard in one early episode of The Sopranos, effectively disqualifying herself from getting a role in later series and the fact that she has talked to Seinfeld co-creator Larry David in recent years without being asked to do Curb Your Enthusiasm. ‘It hurts my feelings. I love that show so much and if he had wanted me to be on it, all he needed to do was ask.’

One show that has required her recent services is 24. Some people couldn’t square the idea of a harsh critic of right-wing tendencies appearing on a show made by self-confessed ‘right-wing nutjob’ Joel Surnow. Did she have doubts about entering the lions’ den? ‘Initially, yes, and then it occurred to me I was unemployed so I said, “you know what; I need a job and they want to hire me”.’ It also soothed the pain that the cast included one of her best pals, Mary Lynn Rajskub who, as the acerbic, prickly, attitude-laden Chloe could have offered advice on how to deal with Jack Bauer bellowing in her face. ‘Like all Canadians, Kiefer Sutherland is unbelievably nice and polite. No one enjoys having a person scream in your face while standing one inch apart and it’s designed to make me look foolish because I’m defending the constitution and the law. And on that show, they want to make anybody who defends the constitution and the law look weak.’

Born in New Jersey in 1964, Garofalo spent much of her upbringing in Texas due to her dad Carmine being a bigwig for Exxon. Although she says her father has a different memory, she recalls simply taking all his worldviews (Republican, religious) as gospel. ‘He’s a very bright guy and a nice one but his politics are right wing, though I didn’t know that when I was younger. But when I expanded my horizons I realised that he had been misled and I had been indoctrinated.’ Her epiphany arrived when visiting friends at Wheaton College near Rhode Island, a historically all-female establishment which only started to allow men to enrol in 1988. ‘We were having a political discussion and I was trotting out all my father’s tropes and wisdom when this very educated woman looked at me square in the face and said, “you’re a fucking asshole”. Everyone at the table agreed and I was asked to leave. On that sad drive away from Wheaton, everything became clear to me and as horrible as that was, it was a real turning point.’

As well as having a switch of views, Garofalo was turning her body into a message board, getting her first tattoo when she was 18 and developing a real taste for the art form. ‘I can’t give blood now because my first one was back in the 80s with pre-sterilisation needles. Nowadays, getting a tattoo is the most normal thing in the world, everybody gets them. In the 80s, it wasn’t quite so normal for middle-class suburban kids to have them and my dad was so mad about it. He said that only long shoremen and sailors got them.’

Comedy became the obvious route for her to get on in life and she made in-roads on TV with regular appearances on The Ben Stiller Show (whom she dated for a spell) and on Saturday Night Live (which she has often described as the worst experience of her comedy career) before taking to the stand-up stage. Once up there, she opted to eschew one of the key practices of the form: if you can’t just make stuff up, then at least embellish the truth beyond recognition. Garofalo is having none of that, knowing that people will spot a faker a mile off who has been telling the same story for years while claiming it’s something that happened to them on the way to the show. ‘My set is always changing and open to revision and whatever happens in the moment. I’m not a particularly strong joke writer per se, and everything I say is true. There’s nothing that I pull out of thin air; I don’t make anything up and I don’t lie to you whether I’m talking personally, professionally, politically, observationally.’

So, it must have miffed her slightly to have been lumped in with the slightly fake Hollywood liberal establishment (Clooney and co) which was ceaselessly mocked by Trey Parker and Matt Stone on Team America, a movie which resulted in a nasty ending for Garofalo. ‘My puppet got its head blown off. When I ran into those guys on the street I said the least they could do was to send me my puppet. They took down my address but they never sent it. That was mean. Probably meaner than blowing my head off.’ Such a gory demise was never likely to occur in the other major animated feature she has appeared in, as the prickly, acerbic, attitude-laden chef Colette in Pixar’s Ratatouille.

With her imminent arrival on these shores, Garofalo is coming with some knowledge of the current crop of British-based stand-ups, and she has great admiration for the stage presence, comedy craft and brazen attitudes of Reginald D Hunter and Jim Jeffries (‘I don’t know how, but he managed to make child molestation funny’). Once her Edinburgh run is over she’ll return to the States and back into the bearpit that is contemporary American politics. She was a former radio co-host of The Majority Report on Air America and will crop up there from time to time but she is not afraid to step out of her comfort zone and confront the enemy by offering an alternative opinion on Fox News.

Does her propensity to appear on shows with people who are inbuilt to loathe her views an act of bravery? ‘I don’t know if it’s so much brave as ridiculous. It’s a fools’ errand to go on Fox News and think you’re going to have a reasoned discussion with anybody about anything. I learned that this was not a forum where adults converse; it’s actually shocking when you meet those people and try to talk to them. It’s like being back in high school where the jocks dominated the hallways and said things that are not governed by reason.’

With Bush now gone, the US satirical community’s main tool has been swiped from them, but maybe hope springs eternal with the existence of Sarah Palin, the hockey mom who reinvigorated the Religious Right during the last presidential campaign. ‘I don’t think she’ll ever go away as she is a true narcissist. And I say that as a narcissist. At least I have the decency to hate myself whereas she doesn’t seem to have any decency.’

Janeane Garofalo, Gilded Balloon Teviot, Bristo Square, 0131 622 6552, 6–15 Aug, 8.30pm, £12 (£11).