There's a note Keith Fleming wrote at the top of his script for Macbeth, in which he plays the title role in a new production of Shakespeare's Scottish play before it opens in Perth this week, then visits The Tron in Glasgow.

"Human nature, baby," the note reads. "Grab it and growl!"

This is a quote attributable to Jack Torrance, the manic anti-hero of Stephen King's horror novel The Shining, brought to the big-screen by Stanley Kubrick in 1980, with Jack Nicholson as alcoholic writer Torrance. This says much about Fleming's approach to playing Macbeth, because, while Rachel O'Riordan's production looks set to remain faithfully concept-free and true to the bard's words, in terms of pinning down his character, Fleming is as steeped in pop culture as it gets. It's the wilder characters in particular he leans to, icons full of wounded machismo and a dark underbelly beneath the bluster.

"He's a bit Tony Soprano," Fleming says of Macbeth, "a bit Malcolm Tucker, a bit Jack Torrance, a bit Walter White from Breaking Bad. He's a warrior. He's a good man, but as the play goes on there's a rage inside him. He has to adopt many different personas throughout the play. He's always been looking outwardly, but by the end of the play he has to look inside himself to see who he is. He's looked outwardly too much, and he has this realisation that once deals are done, they can't be undone, with all the stresses that brings, and what it does to your mind.

"We're focusing on the deconstruction of a macho man," Fleming explains. "A lot of productions focus on Lady Macbeth as this evil force behind Macbeth, but we are not approaching it that way. We are also looking at the fact that at the time the play is set, people did believe in witches, and that witches could bring down a king, so that belief in the supernatural world is very prominent.

"Something that's quite often left out of Macbeth as well is the politics of the play. Duncan is often painted as this nice old man, but he controls Macbeth, and publicly snubs him by not offering him next in line, but keeping him close anyway. It's a very Goodfellas thing."

At the time of talking, Fleming and the rest of director O'Riordan's cast have just run the second half of the play in full after doing the same with the first act the day before. This has allowed Fleming to join up Macbeth's psychological dots.

"I don't want to play it all on one note, with Macbeth as this macho guy," Fleming affirms. "He's a guy who's done some things, and has to live with the consequences of that. He's been busy upsetting the universal order of things, but he didn't think of what the consequences might be, which then becomes a mental and psychological curse."

Fleming isn't being melodramatic here. As part of his research, Fleming met with a psychiatrist, who read Shakespeare's play.

"He pointed out how much Shakespeare seemed to understand about human behaviour," Fleming observes, "and how he recognised disorders that hadn't been defined yet. It's not just the guilt of murdering Banquo with Macbeth. It affects the brain at every level, so it's been interesting in that way, because it's something you have to immerse yourself in totally."

This isn't anything new for Fleming. It was the same when he played the young Peer Gynt in Dominic Hill's epic Dundee Rep production of Colin Teevan's potty-mouthed contemporary take on Henrik Ibsen's rollicking saga of one man's getting of wisdom. It was the same too when Fleming took the lead in Barflies, site-specific auteurs Grid Iron's close-up compendium of some of Charles Bukowski's booze-soaked short stories. Fleming played Bukowski's alter-ego, Henry Chinaski in the production performed in Edinburgh's Barony Bar.

"I used to get loads of comic parts years ago," Fleming says, "then when I did [Ursula Rani Sarma's play, set in the aftermath of a bus crash] The Dark Things at the Traverse with Dominic, I didn't look back. People say dark parts are more fun to play, so maybe I'm just the prince of darkness, like Jack Torrance."

Fleming grew up in Edinburgh, where he attended the Royal High School. Despite an obsession with drawing and painting pictures of animals, which he sent to wildlife charities, a teacher told him he would make a good Richard II. This and the fact that he was going out with a girl who went to stage school saw Fleming become involved in a school production but, faced with having to give up his job in a local restaurant, he pulled out of the production.

Fleming went to Chelsea College of Art and Design for a year, before studying drama at Guildhall. After graduating, Fleming stayed in London for three years, toured a show to the Edinburgh Festival Fringe and later to Perth. It was here he was spotted by then Dundee Rep artistic director Hamish Glen, who asked him to join its ensemble company for six months. He stayed for seven years.

"I worked out I did over 2000 performances," Fleming says. "There was a security there and a chance to develop and do parts I wouldn't normally be cast in. There was a family atmosphere. Dundee will always be a huge part of my heart, but there came the time that it was time to go."

One of the last things Fleming did in Dundee was Peer Gynt, which scooped him and Gerry Mulgrew, who played the older Peer, the Critics Awards for Theatre in Scotland's Best Actor award.

"It's probably the piece of work I'm most proud of," Fleming says. "It was a huge venture, and one of the shining lights of Dominic's genius and creativity. Barflies was another big proud moment. Again, that was quite immersive. A few weeks after doing Peer Gynt, someone said they saw me in a bar, and that they could see in my eyes that the darkness hadn't left me."

If such lingering demons maybe accounted for being cast in shows with Theatre Jezebel like the equally drink-sodden Days of Wine and Roses, Fleming has also done tours of duty with the National Theatre of Scotland in Black Watch and Beautiful Burnout. For now, though, Fleming is immersed in becoming Macbeth, and is likely to remain so for some time.

"I think it's going to be a very true interpretation of the story, with no gimmicks," he says. "It's quite gritty, in that it recognises you need to go low to get yourself high. It's quite rock and roll."

Like the man said: human nature, baby. Grab it and growl.

Macbeth, Perth Theatre, September 18-October 5; Tron Theatre, Glasgow, October 8-19 www.horsecross.co.uk/perth-theatre

www.tron.co.uk