In 2011, Josie Long expressed concern that her Edinburgh Fringe comedy show, The Future Is Another Place, might overrun its hour-long slot.

"I apologise if it does," she cautioned in the handmade programme notes, "but I hope you can appreciate that the idea of cuts being a necessity is one I'm uncomfortable with at the moment."

It was scrawled in photocopied biro, fanzine-style, and everything about Long's comic genius is right there: grass-roots political activism (she's a fierce critic of Government spending cuts), a punk-spirited DIY aesthetic and an astute, ebullient humour that has seen her hailed as British comedy's most important voice.

As well as being an award-winning stand-up, Long is a cartoonist, broadcaster and writer who is as likely to champion Charles Dickens's wit on BBC Two as she is to pen a play about apostrophes for Radio 4. She recently wrote and starred in a short film by Glasgow's 14c Studios, Let's Go Swimming, which is nominated for two Scottish Bafta New Talent Awards, and she co-runs educational charity The Arts Emergency Service, which helps underprivileged young people study the arts and tackle debt. There's even a Josie Long album forthcoming on Fence Records, the Scottish DIY label whose acts include King Creosote, James Yorkston and The Pictish Trail.

Before that, Long is set to bring her sixth solo stand-up show, Romance And Adventure, to Glasgow International Comedy Festival. It sees the London-based, Kent-raised livewire riff on turning 30, facing doubt and enduring political ennui, with allusions to Godzilla and guerrilla gigging. It's more intimate, less politicised than its incendiary predecessor, The Future Is Another Place. Was this reflective of Long's mindset, or the wider social mood? "I really just write about what's preoccupying me, and what's most important to me at the time," she offers. "So The Future Is Another Place just happened to be all about politics, and Romance And Adventure ended up being about loads of personal stuff."

Romance And Adventure's evolution marked a new creative approach for Long, who has performed stand-up since she was 14, with a break to study English at Oxford.

Instead of following a set structure, she says: "I spent a week at the start of this doing completely different hour-long show ideas. For the first couple of previews I spent 10 minutes interviewing the crowd about whether or not they could drive, and whether they'd ever put up curtains, because I wanted to use that in the show. I was like, 'These are the symbols of adulthood,'" she laughs. "I think I even did a survey on Twitter, asking people if they'd hung a pair of curtains."

Twitter's function as a grass-roots conduit chimes with Long's DIY ethos (homespun programme notes, cartoon strips, indie-pop playlists), and her social and political activism. She is a passionate advocate of protest group UK Uncut ("they brought all this tax stuff onto the agenda; they helped make it a part of the discourse"), and a vocal supporter of the No More Page Three Campaign and The Everyday Sexism Project. Long pre-empted the latter's call to arms in the pamphlet for her 2010 production, Be Honourable. "Ladies (and gents!): don't be afraid to call out and challenge sexism – you are not alone!" she vowed.

The No More Page Three and Everyday Sexism cyber-drives have steered feminism into our day-to-day dialogue, but the F-word could still floor a crowd when Long "outed" herself as a feminist a few years ago. "That really amazed me," she says. "When I used to say that kind of thing [about feminism] on stage, it was often quite hostile. I was almost apologetic, you know? That sounds ridiculous now, because the landscape has changed so much in the last few years." Does Long think this shift is partly due to Twitter's clout as a collective mouthpiece? "Yeah, I think that it can add to the sway of any sort of stridency or activism," she suggests.

Long also identifies comedy as a crucial platform for commentary and protest. "What keeps me interested in stand-up is the fact that it's so easy and direct," she says. "You can come out with anything you think, straight away, on stage, and you have total artistic control over what you say and how you're saying it. I love the craft of making stuff and honing a show and putting in jokes and the fact that you can be really political."

Stand-up is a particularly efficient and versatile art form in that respect. "The range you've got is amazing," she nods. "I love the fact that you can be totally earnest and make a complicated political point, and then literally a split second later, you can pretend to fall over, or be a member of One Direction."

Long may parody the charms of Harry Styles for laughs, but there was nary a trace of One Direction when she ruled the airwaves on BBC6 Music, in cahoots with Andrew Collins. Rather, there was rampant evidence of her enduring love affair with Scottish indie-pop.

"All the music I loved when I was growing up is from Glasgow – Belle And Sebastian, Arab Strap, Camera Obscura, The Delgados – so I have a really romanticised view of the place," she says. She cites Glasgow acts among her current favourites, including Randolph's Leap, Malcolm Middleton and Aidan Moffat. (The latter made a celluloid cameo in Let's Go Swimming, as did Belle And Sebastian's Stuart Murdoch).

She's a familiar face on the Scottish indie circuit, whether hosting gigs for Withered Hand, playing Kid Canaveral's Christmas Baubles gig in Edinburgh, or touring with The Pictish Trail, alias Johnny Lynch, who runs Fence. "I really love all those musicians, and I love the fact that Fence do a lot of DIY events – their whole spirit is what I aspire to," says Long of the pop collective started by King Creosote. "Putting stuff out on your own, creating things in a really thoughtful way, programming things with people you love – that's what I want to do."

The album via Fence comes out later this year. "Yeah, I've already given Johnny recordings of some of my shows, and it's hopefully coming out in the summer," she enthuses. "I think it's really important for posterity because the sad thing about stand-up is that I've done all these shows, and they're so meaningful to me – in my head they're like my albums, my back catalogue – but most people haven't seen any of them."

Her bygone hand-drawn programme notes, available as online fanzines, serve a similar purpose: they document her vital work, archive her stars-and-love-hearts-scrawled commands. "Be strident and unashamed! Get active, be imaginative and have fun," says one page that reads like a Josie Long manifesto. They're wise words to live by, writ large, in biro.

Josie Long performs Romance And Adventure at The Stand, Glasgow on March 31 as part of the Glasgow International Comedy Festival, 0844 395 4005