Photograph by Paul Jasmin. Fashion editor: Ethel Park. Grooming by Johnny Villanueva for Olehenriksen.

When Jason Lee decides to take it off, he takes it all off. The 41-year-old actor, who played an affable, overweight and almost comically hirsute slacker on “My Name Is Earl” from 2005 until 2009, recently shed 40 pounds and a whole lot of unnecessary facial hair. “I got chunky during ‘Earl,’ and I had the big mustache for four years,” Lee says. “It was time to clean up my act.”

He slimmed down thanks to a five-week cleanse under the direction of Dr. Bo Wagner, a leading Los Angeles diet guru. “He taught me proper food combining, and how to eat for my blood type,” the actor says. “I cut out sugar, starch and booze, and I’m now as trim as I used to be in my early 20s, when I was skating. It’s really gnarly.” (Lee became a professional skateboarder at 18 and still heads up Stereo Skateboards, the skate company he co-founded 19 years ago.)

His newly svelte physique inspired him to shop for a sharp new wardrobe, more golden-age Hollywood than scruffy sitcom star. “I’ve always been into the ’50s, and the whole James Dean, Chet Baker retro thing,” he says. “It’s nice to see the resurgence of the gentleman, and a return to well-turned-out, well-tailored men, like Jimmy Stewart.”

Lee appreciates heritage and traditional craftsmanship when it comes to possessions and keeps his life on the lo-fi side. He listens to jazz (on vinyl), takes photographs with film, prefers to play old guitars and writes on a Smith Corona typewriter.

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His approach to fashion is equally old school: button-down shirts (always tucked in); vintage glasses; pre-World War II denim from the Stronghold in Venice Beach, Calif.; Alden boots from J. Crew Men’s Shop; ties from Jake Vintage in Los Feliz; and sportswear from WeSC, a Swedish label.

The actor, who plays a clean-shaven cop on TNT’s “Memphis Beat” (and stars in “Alvin and the Chipmunks: Chipwrecked” come December), even vanquishes whiskers the old-fashioned way: “I go for straight-razor shaves at Sweeney Todd’s Barber Shop.”

Lee’s salt and pepper hair is closely cropped these days. “Lately I’ve been slicking it back with a thick, beautiful-smelling pomade called Black & White, and I keep my Mason Pearson comb in my front pocket at all times,” he says. “The shaggy hipster thing is wearing really thin. It’s the age of the man once again. Dudes are turning to quality.”