“I've looked like a 53-year-old man since I was 18. In my face, anyway. My body has caught up now. This suits me.”

Drinking tea and mauling a tomato-and-mozzarella tartine on the patio outside a Los Angeles photo studio, John C. Reilly was explaining how, growing up alongside what looks to be America's final generation of true open-a-movie-solo stars, he'd crafted a career as Hollywood's ultimate sidekick. And how he'd managed to find roles in films this fall and winter that let him share center stage: The Sisters Brothers, a Western; Ralph Breaks the Internet: Wreck-It Ralph 2, his first sequel; Holmes and Watson, another Will Ferrell team-up; and Stan and Ollie, about the comedy duo Laurel and Hardy. “In every one, I have a strong partnership,” he said. He'd been wondering: “Why is that? Why aren't you just a stand-alone movie star? Why don't you just do that? I know a lot of actors, that's their thing. They don't do buddy movies, or they don't do partnerships. Why aren't you like that?”

By the time Reilly and I sat down together, he had the answers. “Number one,” he said, “things like that don't generally come my way.” Reilly—rock-solid, mop of curly hair, brow like a bridge strut—has always understood what Hollywood will and will not give to a guy like him, but he's also spent 30 years figuring out ways to turn looking like a 53-year-old into a basically unparalleled filmography.

“I've finally come to embrace that: This is the way I look,” he said in his French horn of a voice. “I know I don't look like Brad Pitt. I love Brad Pitt. I really do—he's one of my favorites—but I'm never going to be like that guy. I'm never going to walk in that guy's shoes. This is what I'm like, so I'm here. Some people like what I do, and there's something freeing about that.”

Reilly is given to understatement.

“As you get older, this business can kind of typecast you or decide what your limits are for you. So as you get into it, and you're not some new, fresh commodity that everyone's excited to re-interpret for their movie, you start to realize, Well, if I'm going to get more interesting opportunities that challenge me, I'm going to have to start generating them.” He laughed. “It's an obvious thing that just took me a long time to figure out.”

“I’m good at being sincere when acting,” Reilly said. “I’m good at believing what I’m saying.”

Conveniently, his figuring out the industry coincided with the industry figuring out him. “It's like suddenly chocolate ice cream becoming wildly popular,” he said. “I've been here all along. I'm a standard flavor that's been available. I'm not a new flavor. Not the flavor of the month. I'm just chocolate. And goddamn! People like me right now.”

In the '90s, after a childhood among six siblings on Chicago's South Side and a spell in that city's hard-driving, ego-denying theater scene, Reilly jumped to movies—catching small parts, his facility often leading directors to rewrite and expand roles for him. A few pictures in, the Sundance Director's Lab paired him with a young filmmaker named Paul Thomas Anderson. Reilly played the lead in Anderson's star-crossed debut, Hard Eight, and made supporting roles iconic in Boogie Nights and Magnolia. “I was as big a fan as you can be of somebody who'd made five movies,” Anderson told me. “He didn't look like anybody, he didn't sound like anybody else. And that was really exciting.” They grew close, each letting the other into his career. Anderson credits Reilly with figuring out the ending to There Will Be Blood.

One summer, waiting for the financing for Boogie Nights to get settled, they were bored and frustrated. Cops was relatively new back then, and they were obsessed. They'd call each another from their respective living rooms and stay on the phone while they watched. Reilly had a goatee at the time, and Anderson gave him holy hell for it, but when Reilly caved and shaved it off, he realized he looked like a cop. The next step was obvious: “If you've got nothing else to do, take a video camera and drive around,” Anderson said. Reilly explained: “He got me in an L.A.P.D. uniform from a costume friend, and we would drive around” in Anderson's Oldsmobile. “We'd call up, like, Phil Hoffman and say, ‘Phil, we're coming over. Someone called the police because your music was too loud. Just go with it. You'll see when we get there.’ ”