Andre Braugher was having a hard time finding his way into the box. This was a bit unexpected; Braugher, who has won two Emmys, made his reputation in the box, a.k.a. the interrogation room, on the award-winning and — like most Braugher shows — underwatched “Homicide: Life on the Street.” Through most of the 1990s, Braugher played Frank Pembleton, a Baltimore homicide detective who wore designer shirts and philosophized about his Jesuit education and his troubles as a married man. Braugher was so good at interrogation scenes that virtually entire episodes were set in the box, where he broke down criminal types played by the likes of Paul Giamatti and Steve Buscemi.

But that was more than a decade ago. Now he was back, in the role of Capt. Ray Holt, on “Brooklyn Nine-Nine,” a cop show that has more in common with antic sitcoms like “The Office” and “Parks and Recreation” than with hourlong dramas like “Homicide.” Braugher was set to interrogate Detective Jake Peralta, played by Andy Samberg, the show’s star, about some Halloween shenanigans. The only problem was that Braugher couldn’t get through the door without stumbling. He asked the crew for a moment to practice.

“It’s been almost 20 years,” Braugher said with disbelief as an assistant daubed his pate. “You have to step in and stand outside the arc of the door and then slam the door.”

Braugher leaves nothing to chance with his acting. He had spent three hours that morning rehearsing lines with his wife, the actor Ami Brabson. “Andre is like Superman, and improv is his Kryptonite,” says Ray Romano, who starred with him in the TV series “Men of a Certain Age.”

For a full minute, Braugher practiced slamming the door, rattling the set of the show, on a soundstage in Studio City in Los Angeles. To kill time, Samberg entertained the crew with the story of Super Sensitive Bully, a character he created — but never aired — during his time on “Saturday Night Live.” “He starts off all tough with ‘What’s Up, Nerds?’ ” Samberg said, slumped at the table. “And then they say, ‘Don’t call us that,’ and he starts crying: ‘I’m sorry, I’ve got problems at home, my old man whales on me.’ ” The crew giggled. Braugher paid no attention. Finally, he had the door figured out.

The camera rolled as Braugher stepped into the box, deftly, and the door slammed just right. He sat down and confronted Samberg’s character with his discovery: a would-be prank to steal his beloved watch. It was a tricky scene with multiple cutaways and flashbacks. Samberg momentarily forgot his lines and shot Braugher an “I’ve disappointed Dad” look. “I apologize, Andre.”

Braugher shrugged it off with a small smile. They started again, and Braugher’s character pointed out that he still had the watch — he had outduped the dupe attempt. Samberg put on a horror-struck expression. “What? You were behind this? You, you played me.”

Braugher paused, then replied in his slow, mellifluous baritone. “Like Franz Bluheim plays the flute: masterfully.”

The set tittered. It’s doubtful that anyone but Braugher could get a laugh out of name-dropping a fictional Austrian flutist. The “Brooklyn Nine-Nine” cast is mostly comedians, but the Juilliard-trained Braugher often steals the scene.

Shooting continued as Braugher and Samberg each tried different readings. Between camera loadings, Samberg riffed about alternate approaches. Maybe he’d do a bit on a dog’s penis. Braugher said he’d stick with just the dog.

Free-associating, Samberg started talking candy bars: “ ‘Now with three times more nougat.’ What the hell is nougat? Why do I want 300 percent more?”

Braugher paused and then answered in the deeply serious voice he used to narrate openings during three different Olympics for NBC. “Pop. Rocks. Now. With. 100. Percent. More. Rocks.”

Samberg sputtered and did a near spit take.

“Andre, that’s funny.”

Andre Braugher is an actor so in love with Shakespeare that he is saving “Pericles, Prince of Tyre” for later in life. “I’ve never read it because I’d like to see one Shakespeare play that I don’t know what happens,” Braugher told me one afternoon. He sighed dreamily. “I close my ears and hum whenever I hear anything about ‘Pericles, Prince of Tyre.’ ”

A sitcom may seem an unlikely career twist for Braugher, but “Brooklyn Nine-Nine” represents an unorthodox triumph. Despite receiving acclaim for his work on “Homicide,” as well as for playing Henry V in Central Park and for his star turn in the 1989 movie “Glory,” Braugher has had a career of fits and starts. Five post-“Homicide” shows never made it past the second season. In a 1991 Chicago Tribune interview, he described the offers he received this way: “I get a lot of [expletive] scripts, stereotypical unhuman, uncomplex, thick-lipped, long-limbed heathens. I get those, and I throw them in the garbage can. I’m a member of a very complex and richly valued race. I just don’t buy seeing lies about my race perpetuated.”

While things have improved somewhat, Braugher says he still doesn’t get all that many worthy offers. “It’s still there, there’s the vestiges from this ‘third gangbanger from the left’ thing.’ ”

Braugher grew up in the Austin section of Chicago, a neighborhood on the city’s crime-ravaged West Side. His father worked as a heavy-equipment operator for the state, his mother for the Postal Service. They wanted their son to do better. Braugher’s Catholic education included high school at the prestigious St. Ignatius College Prep. His father read his homework nightly and made him redo it if there were excessive erasures or smudges.

“We lived in a ghetto,” Braugher says matter-of-factly. “I could have pretended I was hard or tough and not a square. I wound up not getting in trouble. I don’t consider myself to be especially wise, but I will say that it’s pretty clear that some people want to get out and some people don’t. I wanted out.”

He earned a scholarship to Stanford, where his father hoped he’d study engineering. He was preparing to do so, until a friend told him a student production of “Hamlet” was looking for someone to play Claudius. Soon he was hooked, missing classes to hang out with his new theater friends. His grades dipped. His father was furious when Braugher told him he wanted to become an actor. “We’ve got dancers and singers in our family, and that crap doesn’t go anywhere,” his father told him. He asked his son to name some working black actors. James Earl Jones and Sidney Poitier, Andre replied. His father just snorted. “They’re superstars. Show me black actors who are earning a living. What the hell are you going to do, juggle and travel the country?”

Eventually Braugher won over his dad, and secured a scholarship to Juilliard. Shortly after graduating, he auditioned for the filmmaker Ed Zwick, who was casting “Glory,” about African-American soldiers in the Civil War. Braugher got the part of Thomas Searles, a bookish Northerner whose experience as a soldier is harrowing. Braugher was so green that his co-stars, Denzel Washington and Morgan Freeman, had to show him how to act for the camera.

Braugher received raves for “Glory” but little in the way of follow-up opportunities. Perhaps, he thought, his father had been right. He returned to the theater. Then in 1993, he was called in to audition for a pilot based on David Simon’s book “Homicide: A Year on the Killing Streets,” which Barry Levinson was producing. He didn’t think the audition went particularly well and threw away the lines when he was leaving. But Levinson and Tom Fontana, the showrunner, were hooked by Braugher’s intensity.

“The show began as an ensemble piece,” Fontana says. (The ever-changing cast of “Homicide” also included Clark Johnson, Melissa Leo and Richard Belzer.) “And it became The Andre Braugher Show. All the writers wanted to write for him because he was great and because they wanted to see if they could screw him up, throw him off his game.”

Fontana famously set the show’s fifth episode — in which a tightly wound Braugher and his partner, played by Kyle Secor, try to wring a confession out of a junk dealer for the murder of an 11-year-old girl — almost entirely in the box. Fontana won an Emmy for the episode.

“He could say so much with his eyes,” Fontana says. “We’d write these incredibly glorious speeches for him, and then you would see him just look at someone, and we’d sometimes go: ‘Drop the monologue. He’s already sold it.’ ”

In 1998 Braugher won his own Emmy for his acting on “Homicide,” then left the show and began to pursue film roles. But with the exception of a few minor successes — notably as an angel opposite Nicolas Cage in “City of Angels,” the American adaptation of Wim Wenders’s “Wings of Desire” — his movie career was a disappointment. “I think there is still a subtle prejudice in the industry,” Fontana says. “A certain number of black actors, Latino actors, are allowed to be the famous ones, and the rest have to struggle.”

His big chance to play against type finally came six years ago, when Romano and Mike Royce, creators of “Men of a Certain Age,” were looking for a replacement for Wendell Pierce. (Pierce had bowed out to do the HBO show “Treme.”) Someone suggested Braugher. Romano said, “You mean the guy from ‘Homicide’ that scares everybody?”

Romano and Royce immediately started looking online for signs that Braugher could be funny. “We put in ‘Andre Braugher and comedy’ and for the first time in my life, we stumped Google,” Romano says with a laugh. “We couldn’t find anything.”

Now Braugher regularly outshines the comedians. He traces that success back to the classics, albeit ones more recent than Shakespeare.

“I’m their straight man. . . . When I go back to all those Abbott and Costello routines, especially ‘Who’s on First,’ somebody’s got to be that string to keep the kite from flying away,” Braugher says. “With these guys I’m the string.”

The first time I met Braugher was on a rainy spring night in Manhattan, at a small theater in the East Village called the Paradise Factory. His wife was starring in the New York premiere of “Tough Titty,” a play about coping with breast cancer written by their friend Oni Faida Lampley, who died of the disease in 2008.

Braugher parked nearby and arrived at the end of the performance. (He’d been making dinner for the couple’s three sons at the family house in South Orange, N.J.) I followed him as he ran up and down stairs, checking the bathrooms and turning lights on and off. Braugher was something of a jack-of-all-trades for the show.

“There’s a lot to do with producing — interviews, and you have to make sure the toilets work,” Braugher said, slightly out of breath. “You don’t want someone to leave the show not talking about the performance but the toilets.”

One day he was doing radio interviews, the next he was applying 1,500 stickers to fliers to fix a typo. But he didn’t mind: Brabson, who played his wife on “Homicide,” had paused her career to look after their sons while Braugher searched for the right show. He was happy, he said, to return the favor.

After the performance, the three of us walked through the Village looking for a place to eat. Braugher ventured into a couple of bars. They were all too loud for him. He considered a cast member’s offer to retreat to a nearby apartment for a glass of wine. First he said yes, and then he looked a little panicked and made his excuses. We settled on a generic bar raging with 20-somethings.

“I’ve really been trying to break my addiction to critically acclaimed, poorly watched shows,” Braugher said, sipping sparkling water. One of them, “Last Resort” (2012), in which Braugher played an altruistic, rogue submarine commander, couldn’t figure out whether to be “Band of Brothers” or “Scandal.” Another, Romano’s “Men of a Certain Age,” was never likely to get big ratings when episodes centered on Braugher, Romano and Scott Bakula going for colonoscopies on their 50th birthdays. But he didn’t want to dwell on his disappointments. In fact, it quickly became clear that Braugher would rather talk about anything other than his career. I told him I’d recently had a child, and he immediately told me I needed to have another one. “You have to build a family. You’ll never regret it.”

Brabson tittered. “Well, we had our doubts after our first one with you traveling so much.”

Braugher looked perplexed. “Really?”

It was at that moment that I remembered I’d met him briefly before. We’d sat across the aisle from each other on a Jet Blue flight a decade ago, and he’d spent most of the flight laughing, with his arm around his eldest son.

Braugher put up little resistance when Brabson suggested they move to New Jersey in the late ’90s to raise their family. He never took to Hollywood, and says he rarely went out in Los Angeles. “I marvel at people who have that ability to network,” Braugher said. He related a story about starring with Rob Lowe in Australia in a mini-series adaptation of Stephen King’s novel “Salem’s Lot.” “I remember looking at Rob and saying, ‘Wow’ — you know, he’s a networker, a people person — and I said, ‘This is amazing: we might be polar opposites.’ Rob lives smack dab in the middle of the city, he’s superconnected and he has that connective personality. I get invited to a thousand parties, but do I show up at them? No, I don’t.”

Braugher remains intensely private. He rebuffed me when I asked if I could meet him at his Venice rental, where he stays when he is filming the show; he told me he was happy to talk, but he wouldn’t give up part of his soul. About his personal life, he would only say that there had been “stumbling blocks.” (Braugher stopped drinking alcohol and smoking years ago.) “I won’t go into details, but I have not always been at the top of my game, and that has a cost.”

Braugher looked around the restaurant to see if anyone was watching and then unleashed an incandescent smile. “There won’t be a memoir.”

After “Men” was canceled, the co-creator of “Brooklyn Nine-Nine,” Michael Schur, contacted Braugher about playing Captain Holt. Braugher was intrigued that Holt was a gay man in a stable relationship, whose sexual orientation was never played for cheap laughs. In the process of fleshing Holt out, he has wholly reimagined the trope of the humorless police chief. There’s a moment in an episode last season, when the buttoned-up Holt walks in with a cast on his arm. The detectives try to guess how it happened. Peralta theorizes that he hurt his arm when he tried to smile. Holt walks over to Peralta and tells him that he sprained it in a Hula-Hoop class. He pulls out his phone to show him the evidence and says gravely: “I’ve learned all the moves. The pizza toss. The tornado. The scorpion. The oopsie doodle.”

Peralta looks at him with horror. “Why are you telling me this?”

Holt deletes the pictures, speaking even more slowly. “Because no one will ever believe you.”

“Andre has such a fluency in the world of cop drama, and that works to his advantage,” Samberg says. “Applying the polish and dramatics that you would to something very serious to something very silly is a classic move that I always love.”

A week or so after Braugher’s scene in the box, he and Brabson spent the morning fooling around with their sons before the makeup artists arrived to get them ready for the Emmys. It was Braugher’s eighth nomination, this time for best supporting actor in a comedy. He was up against, among others, Ty Burrell of “Modern Family” — who ended up winning — but that wasn’t what was making him nervous. The host, Seth Meyers, had asked Braugher to be in a live sketch in which he had to get up from his seat and ask for the theater’s bathroom key, a prospect that filled him with some of his old dread about nonscripted performances.

“I’m still not a natural in front of people,” Braugher told me later. “I’m shy. I’m a hermit. But I’m learning a little more; my profile is getting higher because of the show. I’ve been forced to sort of step up.”

The sketch came off flawlessly. A little later, Braugher and Brabson slipped out, skipping the parties and retreating to Venice. “Brooklyn Nine-Nine” was on a weeklong hiatus, and the next day the Braugher family was heading for New Jersey, where Andre could ride his bike, tend his tomatoes and try to beat his kids at H-O-R-S-E. America’s most unlikely funny man had dinner with his wife and was asleep by 11.