There is something incongruous about seeing Ken Watanabe in a light-brown hoodie. He is synonymous with crisp tailored suits. It is like catching James Bond in jogging bottoms. “Hello!” he beams from a cosy corner of his living room, family photos lining a shelf, dark-mahogany cabinets behind him. “Good evening! Or good morning?” he asks from his home in Karuizawa, a resort town in Honshu, Japan, as we chat over video. He has just finished a photoshoot with his boisterous border collie, Dan, who is yelping nearby, desperate to be included.

Even dressed down, the Japanese actor radiates the same commanding presence that he exudes on screen. He is one of the few modern east Asian stars to cross over successfully to Hollywood, which he did with his role in 2003’s historical epic The Last Samurai. At 62, sporting a smattering of stubble, he still looks remarkably youthful.

Watanabe made his name working within the crude templates that Hollywood drew up for portraying east Asian men, but somehow managed to transcend tired stereotypes. In The Last Samurai, he played Katsumoto, the eponymous warrior, who gets the funniest lines; in Inception, he played Saito, a ludicrously wealthy businessman who becomes a crucial part of the dream-hacking corporate espionage team; and in Batman Begins he played the bearded villain who turns out to be a decoy for Ra’s al Ghul, the real bad guy.

Each time, Watanabe outshone his co-stars with his boundless charisma and gravitas – no mean feat, considering they included Christian Bale, Leonardo DiCaprio and Tom Cruise.

He does it again in his new HBO Max/Starzplay series, Tokyo Vice. Ansel Elgort is the lead, playing the real-life American journalist Jake Adelstein, but Watanabe steals every scene he is in. As the grizzled detective Hiroto Katagiri, he becomes a mentor to the overeager writer as he navigates his new job as a crime reporter for one of Japan’s biggest newspapers.

Initially, Watanabe wasn’t sure about the project. “Japanese yakuza versus the cops is a story that has been told before,” he says, his assistant chipping in from time to time to translate (he switches between English and Japanese). “But I liked that it was from the perspective of a young American journalist; that was different. When I heard Michael Mann was directing the pilot, I definitely wanted to do it.”

The fish-out-of-water crime thriller explores Tokyo’s seedy underworld during the 90s, as tattooed yakuza gangs battle it out for supremacy while seductive expats work in gaudy hostess clubs. Illicit hijinks aside, Watanabe thinks the show taps into the core of what makes Japanese people tick. “They keep their feelings hidden. They’re quite modest and shy. But we all have a bright and a dark side to our personalities.” Katagiri exists in a grey space. “There’s no white or black for him. He’s a good husband and father who is very gentle, but as a detective he’s really strong and a bit scary.”

Katagiri is a man with a strong moral compass: upstanding and honourable. Watanabe is often cast as the good guy, playing the brave General Kuribayashi in Letters from Iwo Jima, the kind-hearted Lieutenant Yoshida in Pokémon Detective Pikachu and Katsumoto, the noble leader of a gang of rebels in The Last Samurai. “The most difficult thing was the language,” he says of the third film. “I’d never acted before in English. I tried to get the language right so I could focus on the acting. But really, acting is the same, whatever language you use.”

Edward Zwick’s sweeping drama remains one of Japan’s most successful box office hits, but the film has been accused by critics of perpetuating the white saviour complex. Cruise’s character, the US army captain Nathan Algren, is captured by Katsumoto, but ends up fighting on his side.

“I didn’t think of it like that,” Watanabe says. “I just thought we had the opportunity to depict Japan in a way that we were never able to before. So we thought we were making something special.”

If anything, he sees it as a turning point. “Before The Last Samurai, there was this stereotype of Asian people with glasses, bucked teeth and a camera,” he says, conjuring up images of Mickey Rooney’s abominable performance as Mr Yunioshi in Breakfast at Tiffany’s. “It was stupid, but after [The Last Samurai] came out, Hollywood tried to be more authentic when it came to Asian stories.”

With TV and film executives finally cottoning on to the importance of on-screen representation, a handsome east Asian love interest seems to be all the rage (see Crazy Rich Asians, Last Christmas, Always Be My Maybe, The Good Place and Love Life). But for many years, east Asian actors were reduced to playing nerdy sidekicks, kung fu fighters or villains in the style of Fu Manchu. And no, they never got the girl.

Watanabe did, though. He played the romantic lead in Memoirs of a Geisha, a lavish blockbuster directed by Rob Marshall, and Bel Canto, a slushy hostage drama in which he romanced Julianne Moore. How did it feel to be a Hollywood heart-throb? “I don’t create my characters that way, so I wasn’t aware that I was being looked at that way,” he says.

Similarly, when The Last Samurai earned Watanabe an Oscar nomination for best supporting actor – making him only the fourth man of Japanese heritage to be shortlisted in that category – he was unaware of the significance. “Then I realised it’s only five people every year, in all of Hollywood, that get nominated. It was an amazing honour.”

Watanabe was born in the mountain town of Koide, Niigata, about 40 miles north of where he lives today. His parents were teachers and he loved going skiing with his older brother. He spent years studying the trumpet, diligently performing with his high school band, hoping to become a musician. But when Watanabe was 13, his father, a calligraphy tutor, became seriously ill and the family could no longer afford music lessons. His dream was to go to music school, he says, “but I had to give up my musical aspirations. I realised I had no talent as a musician. But I still wanted to find a way to be creative, so I decided to try acting.”

He moved to Tokyo and enrolled in the revered drama school run by the theatre troupe En. “I wasn’t hugely ambitious,” he says. “I just needed an outlet to express myself. But other actors in my class were so focused; I didn’t want to get left behind.”

After appearing in the play Shimodani Mannencho Monogatari, led by the acclaimed theatre director Yukio Ninagawa, Watanabe soon branched out to TV and film. One of his most popular roles came in the 1987 historical series Dokuganryū Masamune (One-Eyed Dragon Masamune), in which he starred as the samurai Date Masamune. (Watanabe has portrayed many samurai over the years – he even voiced a samurai robot called Drift in 2017’s much-derided Transformers: The Last Knight).

Acting proved addictive. “That feeling of all the cells in my body becoming someone else – I’m not sure if you can call it fun, but it’s something that I can’t stop doing and can’t get enough of.”

But in 1989, just as his career was taking off, Watanabe was diagnosed with acute myeloid leukaemia. He was 29. He was forced to drop out of Heaven and Earth, a big-budget samurai epic, as he received chemotherapy. He ended up taking a year off, reading books nonstop while he recuperated. “I just wanted to recover and live life,” he says. “I didn’t really think about acting, because my mind was more occupied about what was going to happen to me … Things have progressed now, but 30 years ago, the probability of recovering was much slimmer, so it was more serious.”

Watanabe had a relapse in 1991. This time, he was determined to pick up his career again. “I knew that people were rooting for me and waiting for me to return.” It motivated him to get better, but it was a gruelling experience. “The first time, I didn’t know what was going on, what kind of treatment was available and how successful it was going to be. Everything was new to me. But the second time, I had already gone through it, so I was just thinking about having to do everything all over again. That really brought me down; just the thought of it drained me.’”

Even after he was given the all-clear, Watanabe continued to be plagued by serious health problems. Just before he started filming The Last Samurai, he discovered that he had contracted hepatitis C from a blood transfusion he received as part of his treatment for leukaemia. Then, in 2016, while on a break from performing in a Broadway production of the Rodgers and Hammerstein musical The King and I, Watanabe was diagnosed with stomach cancer.

Luckily, it was caught early and he was able to have surgery to remove it. “When I found out, I was more concerned about being able to recover quickly enough to go back to the stage. That’s all I was thinking about. I didn’t really think about whether I was going to succeed or fail with the cancer.”

Watanabe is surprisingly sanguine when he talks about his health struggles. “When I have these illnesses, it is really difficult, but I actually think of myself as a lucky person. Everything that I experience, even my illnesses, becomes a part of me that helps me as an actor. So, in that sense, it wasn’t a bad thing. It’s who I am. In my 20s, I was a lead in a major Japanese TV series; in my 40s, I was able to do The Last Samurai; and in my 50s I did The King and I, so I consider myself really lucky to have had all these opportunities.”

His illnesses have taught him to cherish what he has, Watanabe says. “Each little thing in my life, I learned to treat it as more precious.”

He divorced his second wife, the Pachinko star Kaho Minami, in 2018 after 13 years of marriage. While they were together, he adopted Minami’s son from her previous marriage. Watanabe has two other children – Dai and Anne, both actors – with his first wife, Yumiko Watanabe, and five grandchildren. Does he have someone special in his life now? He smiles and waves as if to leave. “Of course I have!” he laughs. His hand shoots up again, but this time he gives me the thumbs up while nodding vigorously. “It’s a secret!” he adds, conspiratorially.

He is much more effusive talking about K-port, the cafe he set up in 2013 to help the community in the city of Kesennuma. Watanabe was heartbroken after the devastating triple disaster in 2011, when an earthquake and a tsunami struck Japan’s north-east coast, triggering nuclear meltdowns in Fukushima. More than 19,700 people were killed. Kesennuma was heavily damaged.

“I went around to 22 different places,” he says. “They had camps set up for all the people that lost their homes. From what I’d experienced, having faced death, I could understand a little bit of what that feeling of devastation was. I had a really powerful feeling inside of me that I wanted to do something for these people. After talking to them, I realised that I could create a cafe where people can get together.”

Watanabe visits Kesennuma regularly, whenever he is in Japan, although he had to put his trips on hold during the pandemic. The actor helps to develop dishes on the menu at K-port and sometimes even serves customers.

In his downtime, he likes to cook, read and keep up with his favourite baseball team, the Hanshin Tigers. Having enjoyed such a groundbreaking career, he no longer sets himself goals as an actor: he is happy to leave space to be surprised. “I realised that somebody offering me a role that I’d never thought about is such an incredible thing.”

Does he have any regrets? He flashes me a big grin. “I have a lot! But a life without regret isn’t really fun or interesting. I reflect on my mistakes and learn from them.” With that, he throws out a quick salute and we say goodbye. Dan needs to be walked and there are unexpected opportunities, more wonderful than he can imagine, waiting for him, just around the corner.

Tokyo Vice is streaming in the UK on Starzplay