Jeremy Piven has a sophisticated charm; he knows how to work an audience. Indeed, he’s been doing it since he was a child. Piven grew up on stage, nurtured by parents who were both actors and directors.

He has been taking the imaginations of audiences on a journey for decades – from Jerry Capen in The Larry Sanders Show to Spence Kovak in Ellen, from Trevor Hale in Cupid to Buddy Israel in the movie Smokin’ Aces. As an actor, Piven makes you think, and he takes you on a visceral roller coaster ride.

We see this particularly with Ari Gold, his character in Entourage, a type-A movie agent known for his lack of impulse control and for saying the first thing that comes to his mind. Gold walks into a room, and people know he’s there. He’s like a proverbial Bucking Bronco.

Piven’s portrayal of Gold won him the most prestigious trophies you can bring home as an actor in TV – three Emmy’s and one Golden Globe. It’s no wonder then, that Piven was cast to play the lead in Mr Selfridge, now in its fourth and final season.

Piven plays the titular character, Harry Gordon Selfridge, a charismatic business magnate with a grand vision to change the world of retail. He also has a few vices. Well, mainly two vices – womanising and gambling.

The story is based on the book Shopping, Seduction & Mr Selfridge by Lindy Woodhead. It centres around Selfridge’s ambitions to revolutionise the shopping experience. As Piven explains, “he used retail as his theatre; he changed the game completely. He made people feel welcomed and special.”

Prior to jumping on the boat to London and starting Selfridges & Co in 1908, Selfridge worked under the tutelage of Marshall Field at his store Marshall Field & Company in Chicago. Chicago was also were he met his wife, Rosalie ‘Rose’ Buckingham. Marshall Field’s was started in 1852 and lasted all the way until 2005, when it was acquired by Macy’s. In the late 1800s, Selfridge played a major role in the success of that department store. He worked there for 25 years in total, and became a junior partner in the company. “He asked Marshall Field’s if he could have his name above the door – Marshall Field’s & Selfridges – and they respectfully declined,” says Piven. London was calling.

“When he was visiting England – and this is what really made him start Selfridges in London and not the US – he noticed that they they weren’t huge on customer service. And he just thought, wow, there’s a huge opportunity here. I’ll take my credo to England; treat people incredibly well; and put on a big show – and it will work. And guess what? It did. Here we are talking about Selfridges more than 100 years later,” Piven says. Selfridge did indeed change the world – not only retail, but business at large – with his philosophy that the customer is always right.

What Piven does best as an actor is take you through several stages of emotions with a character. There’s a period in the Mr Selfridge series where Selfridge is cheating on his wife – Piven as an actor had to walk that line without his audience falling out of love with the character. It’s a historical fact that Selfridge struggled with womanising and gambling. He wasn’t an alcoholic or a drug addict; he just really loved women and cards. “It’s beautiful and tragic what happened to this guy – and that’s why they call them dramas,” says Piven. “I mean, he had a lot of drama in his life. He desperately wanted to do the right thing and loved his wife. But he couldn’t help himself – and I think he was a slave to his urges and desires, and tried to keep them under control.” Selfridge wasn’t perfect; he had his rough spots. But as an historical figure he forever changed the way we shop.

When I ask Piven about his stints in London while working on the show, he’s most excited and animated about the capital’s theatre scene. “In all of my spare time, I actually go to the theatre,” he says. “I saw a brilliant production of Hamlet with Benedict Cumberbatch. And I saw Othello with an actor named Rory Kinnear playing Iago, which just blew me away. It’s a constant inspiration for me,” Piven explains.

Theatre is, after all, home to him. It stimulates his mind and takes him back to his roots. His parents Joyce and Byrne Piven, two successful actors and directors in their own right, encouraged him onto the stage early, at The Piven Theatre in Evanston, IL, USA. “My parents started The Piven Theatre about 40 years ago. They just wanted a place to call their own. And to be able to have their own corner of the world where they could teach people how to act as well as put on their shows. And have control over their art. We’re in a business where traditionally we have no control: actors sit by the phone and wait. Or, you can take action – and that’s what they decided to do.

I have a lot of dumb ideas about where to put my money. Fortunately, I have a business manager

“Most of the kids at the theatre are on scholarships – and to this day my mother is doing her thing and is very active. We’re in the midst of getting a new theatre right now, so – as my mother says – we can continue my father’s legacy. And that’s where I studied from the time I was eight years old. They threw me up on the stage with them, and that’s where I started doing my thing.”

Unlike many child actors, there isn’t a hint of resentment, though – he’s more than happy with his trade: “I can’t fix your car, I can’t drive a plane, I can act. I can act without stopping, without people coming in and padding me down. I’m very low maintenance. I come to work, I come ready to play, and I love it.”

Spending so much time playing money men, including Ari Gold and Harry Selfridge, is Piven any good at looking after his own finances? “I have a lot of dumb ideas about where to put my money,” he says candidly. “Fortunately, I have a business manager who I’ve been with my entire career. He’s very conservative; he’s the most conservative person in my life. He’s great: he worries about me – I have strange ideas – but he bears with me, and we’ve done alright.

“One of the things I have done – even when I had little money – was invest in property. I don’t know much about the game, but I know enough, so I did that.”

As to new projects on the horizon, Piven does what he does best – and leaves it up to our imagination. “You’ll find out soon. I don’t want to jinx it, but it’s perfect timing. I gotta go walk out the door and meet on it now,” he says. Whatever it is, expect it to be good.

For now, we will just have to enjoy the new – and final – series of Mr Selfridge. Piven says: “When you look at all four seasons and what we were able to achieve, this is the work I’m most proud of. It tells the story of a man’s life, and very few TV series truly have a beginning, middle, and an end. But this one does.” As for Piven, he’s not going anywhere – he’ll continue to charm audiences for years to come.

The final season of Mr Selfridge is on ITV now.