Gary Oldman stars as George Smiley in Tomas Alfredson's ‘Tinker, Tailor, Soldier, Spy.’ (Jack English)

‘In my notes . . . .” Gary Oldman is waxing professorial, drawing his words out in a donnish drawl. The actor is seated behind an ornate desk in an ersatz “secret” room at the Spy Museum, a borderline-cheesy replica of a spy’s office in a fictional near-Eastern country. Oldman — who plays the British spy George Smiley in the new movie “Tinker, Tailor, Soldier, Spy” — slips right into character, peering over chic translucent glasses and smiling broadly under an avuncular mustache.

As convincing as Oldman is, on this day he cuts a decidedly more dashing figure than Smiley, John le Carre’s un-prepossessing master of Cold War tradecraft. Smiley would never wear such smart glasses, for example, nor could he pull off the navy-blue scarf printed with stylized horses. In fact, the great challenge of playing Smiley is giving his recessive character just enough life to be interesting but with enough passivity to be convincingly invisible.

“It’s a bit like rubbing your tummy and tapping your head at the same time,” Oldman says. He speaks slowly, considering each word with exacting care. “One hopes, just by the fact that one’s an actor, that you have some charisma, that when you’re on the screen people want to watch you. But then you’re trying to play someone who has anti-charisma.”

Of course, for anyone who remembers the 1979 miniseries of the same name, “Tinker, Tailor, Soldier, Spy” has already been definitively adapted. What’s more, Smiley has been definitively portrayed, by no less than Alec Guinness, perhaps the finest screen actor of his generation.

“I didn’t say yes immediately,” Oldman says of the inevitable comparisons, “because I thought, ‘How could one sort of slay that dragon?’ But in the end, I sort of played a trick with my head. I thought, ‘Well, there’s more than one Romeo; there’s more than one Hamlet; there’s more than one King Lear — so it was like a reinterpretation of a classical part.”

Gary Oldman during a November visit to the International Spy Museum in Washington, D.C. (Matt McClain/FOR THE WASHINGTON POST)

It takes nothing away from Guinness’s genius to say that Oldman has reinvented Smiley, lending the character more of an edge, a whiff of physical danger and relative youth (Guinness was in his 70s when he played Smiley; Oldman is 53). Although Smiley is still the watchful, quiet Everyman whose chief goal in life is not to be noticed, Oldman has found a vein of vigor and even anger in a man who, when “Tinker, Tailor” opens, finds he’s been betrayed by two people: his wife, Ann, and a mole within the British intelligence agency MI6, nicknamed the Circus, where he has worked his entire adult life.

In reading the book, “I discovered that there’s a little bit of a sadist, a meaner side to George,” Oldman says. “It’s what I call the tickle. ‘I’m just going to tickle them a bit, get them on the back foot.’ You know with passive aggressive people, you never quite know if they’re insulting you? It causes a sort of chemical reaction in your body. There’s a shift in the temperature, but you can’t quite work out what it is, what he does. And that’s why he’s the master interrogator.”

For Tomas Alfredson, who directed “Tinker, Tailor, Soldier, Spy,” Oldman’s performance as Smiley exemplifies the art of screen acting, wherein the artist and the camera engage in a subtle interchange that creates an expressive vocabulary all their own. “You can clearly see . . . that this man has done so much work to dare to do this little,” Alfredson says. “You can’t be 22 and do George Smiley.”

If Oldman filling Guinness’s shoes strikes one generation as apostasy, for anyone who was around to see Oldman’s breathtaking breakout performance as punk rocker Sid Vicious in “Sid and Nancy” (1986) and the playwright Joe Orton in “Prick Up Your Ears” (1987), it makes perfect sense. Oldman burst on the scene as a visceral, uncompromising actor whose performances were marked by startling physical transformations and blazingly intense characterizations.

But in the mid-2000s, Oldman’s career seemed to take a turn. Suddenly, he could be seen chiefly in small supporting roles in “Batman” and “Harry Potter” movies — delivering fine character performances, surely, but in roles that left many of his admirers scratching their heads.

It turns out that Oldman has an excuse: He spent the past decade being a full-time single dad to two sons he had with ex-wife Donya Fiorentino. (He was married twice previously, to the actresses Lesley Manville and Uma Thurman.)

“These last 10 years have been the Batman trilogy, the monster Harry Potter and bringing up my boys, really,” he says, simply. “That’s my biggest project. . . . I woke up at 42 years of age living in Los Angeles as a single dad. And I thought, ‘I’m either going to be a dad who’s away or a dad who’s around.’ And it was the second.”

Three years ago, Oldman married British singer-songwriter Alexandra Edenborough, who texted him mid-conversation. “They’re getting up to go to school,” Oldman beams. “To say things are good at the moment . . . . .” he trails off. “But you still have those anxieties as a performer and an actor, writing a script in your head. You hear people saying, ‘He’s playing Smiley, who the hell does he think he is?’”

Who he is, for one thing, is someone on most Oscar prognosticators’ short lists for best actor nominees. He has just filmed “The Dark Knight Rises,” Nolan’s latest Batman film, as well as a handful of smaller movies, but says that now he’s ready to direct again. (His directorial debut was the acclaimed 1997 realist drama “Nil By Mouth”). There are even whispers of another Smiley movie, perhaps an amalgamation of le Carre’s “Smiley’s People” and “The Honourable Schoolboy.”

After all, the machinations of Cold War Britain aren’t terribly far removed from the geopolitical back channels and corporate knife fights that grab headlines every day. “It’s still relevant. To me, only the faces change,” Oldman says, pushing away from the desk. “Sometimes I just have to say to myself, ‘The world is a mess, and it’s perfect.’ Always has been.”

Tinker, Tailor, Soldier, Spy

opens Friday at area theaters.