Craig Ferguson's return to Scotland has been relatively painless. For his guest role in Still Game last year, in which he played a suave stuntman, the 57-year-old Cumbernauld native recalls meeting the sitcom's creators Greg Hemphill and Ford Kiernan in Los Angeles and asking them to write a character for him. 'And they wrote the part of a phoney prick who comes back from California!'

Ferguson laughs, hard, about his first UK television appearance in a quarter of a century. Now back again, ensconced in Glasgow's West End for the foreseeable future, the prodigal stand-up, actor, author, late-night chat show host and American citizen is feeling considerably more relaxed in the country of his birth, no longer the recriminatory exile. 'I really loved doing it,' he explains. 'A lot of the crew were people I'd worked with 30 years before at BBC Scotland. And it was therapeutic because I realised that it was OK for me to come here and work; everyone was perfectly nice. I'd wanted to come back and they gave me a great way in.'

Tellingly, Ferguson's 1996 US breakthrough was playing pompously posh English boss Nigel Wick in The Drew Carey Show. There, he was channelling his resentment of a British media and showbusiness establishment that had been reluctant to embrace the hell-raising, Glaswegian ex-punk. Ferguson made his name a decade earlier at the Edinburgh Fringe as the ultra-aggressive, ultra-patriotic folk singer Bing Hitler. But his relationship with the UK soured and his alcoholism left him suicidal before he left for a clean break in America.

Sober 27 years now, he can afford to be magnanimous. 'There are some good people here and some arseholes,' he maintains. 'And there are good people and assholes in LA. It was me. I was at a different place. If you weren't helping me, you were in my way, that's how I used to feel. Nowadays, if you're not helping me, that's alright. If there's anything a wee bit of success gives you, it's a chance to fucking relax. And if it doesn't, you've got bigger problems. And certainly, I had those. But I dealt with them as well. In all honesty, for me it was about growing the fuck up.'

As James Corden's predecessor hosting The Late Late Show, Ferguson disrupted the cosy US late-night landscape, establishing a greater spontaneity, flirtation and rapport with returning guests like Carrie Fisher, Stephen Fry and Robin Williams. He was given the prestigious Peabody Award for his interview with Archbishop Desmond Tutu, an icon whose presence induced as much trepidation in him as meeting the Sex Pistols, Buzzcocks and the Damned, bands he'd revered in his youth.

The only fears that Ferguson has now concern his mortality and returning to the Fringe. He cautiously dipped his toe into the latter two years ago, recording a radio show at the festival. And his appearance at the Playhouse, his first UK stand-up in 25 years, will probably be his Hobo Fabulous show's swansong. Already toured around the US and Canada, it's arriving on Amazon Prime in the winter. Nevertheless, it feels like a watershed moment.

'Yeah, it does,' he admits. 'I'd never become so complacent that any gig doesn't feel like a big deal. But it's the base of operations for me, isn't it? I started out in Edinburgh, fucking hell, I don't know, 1986. So that's 33 years ago. A Jesus of a lifetime ago.'

Anyone who's read Ferguson's entertaining but unapologetically spiritual new memoir, Riding the Elephant, will recognise the tales of scuppered dates and losing his virginity in Hobo Fabulous, the angst of his teenage desperation and punk impatience reframed. 'Stand-up for me is a lot like playing a musical instrument. When I started out doing the Bing Hitler stuff, I knew three chords and played them very loud, over and over again. And that's perfectly appropriate when you're young. And I've still got the same instrument, I'm still a man on stage talking into a microphone. But I'm not 24. I don't want to pretend that I'm still angry about stuff that I don't fucking care about anymore, that would just be silly. My only ambition is to be authentic, not pandering to someone else's idea of who I should be.'

Eschewing politics and, to a great extent, current affairs (having ditched his phone's internet browser and ceded control of his social media to his tour manager), Ferguson still speaks candidly about his loves and hates. 'The hardest time I had in Hollywood was the pretend niceness everybody has. It's very weird, like the court of some mad Austrian emperor in the 17th century where everyone has to like a certain thing or believe in a certain "truth". Pretending to make other people comfortable makes me uncomfortable.'

Instead, he seeks peace in eloquence. Currently writing a novel about Merlin and St Mungo, Glasgow's patron saint, he's aspiring to mythology. 'But it's probably just rambling nonsense,' he admits. 'When something's painful, distance helps. And if you can transfer an emotion or something you're not proud of into a document that you are proud of, there's release in that.'

Like his tattoos which commemorate his transatlantic journey and pay homage to his loved ones, 'at first it's painful and vivid. But as they fade into your body, telling the story of your life, they soften and become part of the landscape and you don't remember the pain. It's just something that's there now.'

Craig Ferguson: Hobo Fabulous, Gilded Balloon at Edinburgh Playhouse, Greenside Place, 11 Aug, 8pm.