ABOUT 15 minutes into his stand-up set in his film “Laugh at My Pain,” following bits about his inability to spend money as lavishly as his athlete friends and the strange performer he hired to play SpongeBob SquarePants at his daughter’s birthday party, Kevin Hart pivots to a routine about his father’s cocaine addiction.


“When you first hear it,” says Mr. Hart, a compact, energetic comedian, “you’re like: ‘What? Your dad was on drugs? That’s crazy.’ ” Still smiling, he adds: “It’s not that bad. I’m going to tell you why.”


Among the advantages to his father’s habit? “There’s no such thing as a bad idea to a cokehead,” Mr. Hart explains. Among the downsides? When your dad shows up stoned to a spelling bee and roots for it like a sporting competition.


Then, to the delight of his audience, Mr. Hart imitates his father’s entrance, bobbing his head, pumping his arms and shouting in a sing-song voice, “All right, all right, all riii-iiight!”


Mr. Hart has turned this expressive re-enactment of his father’s coked-up battle cry into an improbable catchphrase — and “Laugh at My Pain,” along with it, into a grass-roots hit — earning him an ever-widening fan base and, on Thursday, a hard-won gig hosting the MTV Video Music Awards.


Last month his preparations for the show brought Mr. Hart, 33, to New York, where he explained over a lunch in Times Square that his comedy was not always so confessional but that the more personal and revealing it has turned, the more successful he had become.


“Once you tap into that,” Mr. Hart said, “is when your career takes off.”


In a career that spans more than a decade, Mr. Hart finds himself in its most explosive phase so far. Since “Laugh at My Pain” was released last September, that independently produced feature has grossed more than $7.7 million on a budget of about $700,000. “Think Like a Man,” the Sony/Screen Gems romantic comedy in which he was a member of an ensemble cast, has sold more than $91 million in tickets since April.


On TV Mr. Hart has appeared in a recurring role on the hit ABC sitcom “Modern Family.” During the New York Comedy Festival in November, he will play two shows at Madison Square Garden.


For all that he has accomplished Mr. Hart is supremely confident that even greater triumphs await him. And the higher he climbs, the more certain he feels that he must be candid with audiences about everything that has happened in his life.


“Because of what I do, it has to be an open book,” he said. “But right now this is a book that is being written.”


As Mr. Hart, dressed entirely in black, tucked into a chicken Caesar salad and a glass of pinot noir, he chattered with his colleagues Harry Ratchford (who is officially director of operations for team Hart) and Dwayne Brown (his executive assistant), who sat at a nearby table.


Back and forth the three men traded smartphones and an iPad as they excitedly reviewed ticket-sales data for Mr. Hart’s Madison Square Garden shows and details of the celebrity-studded commercials he’d be filming for MTV.


But Mr. Hart, who stands 5 feet 5 inches, could easily recall a time when he was still playing the comedy clubs of his native Philadelphia under the stage name Lil’ Kev the Bastard and did not warrant much support or enthusiasm.


“I was trying to be everybody,” he said. “I was so confused I didn’t know what to do.”


During his professional initiation in the late 1990s, Mr. Hart said, he fell under the sway of elastic and physical comedians like Chris Tucker (the “Rush Hour” star) and J. B. Smoove (who would later join “Curb Your Enthusiasm”) and tried too hard to imitate their acts.


Keith Robinson, a veteran comedian who became Mr. Hart’s mentor, recalled one fateful night he saw Mr. Hart perform at a club called the Laff House.


“The first show he bombed,” said Mr. Robinson, who has also worked with comedians like Wanda Sykes and Patrice O’Neal. “The second show he killed, but he was actually better the first show, because he was being more of himself.”


Mr. Robinson took Mr. Hart under his wing, but not before giving him a stern lecture about finding his authentic voice. “The material that’s going to take you farther is the material that’s drawn from you, that you’re going to struggle with,” Mr. Robinson said. “But it’s better to struggle with your stuff than do the stuff everybody’s doing.”