Every year, a gaggle of gagmen and funnywomen set out in pursuit of that holiest of TV grails: the first-person sitcom — a show written around a comedian’s distinctive personality. Nothing can curb their enthusiasm for stepping out of standup or sketch comedy into their own keylight.

“Most comedies work when there’s a strong personality at the center,” says producer Judd Apatow, who has godfathered Garry Shandling and Lena Dunham in their sitcom quests. “And though most of it is fabricated, the core of it comes from truths about a lead actress or actor.”

The secret seems to be finding the topliner’s sweet spot where real-life personality, stage persona and fictional role magically click into place.

In fact, this kind of comedy is older than television itself. Nobody, they say, was kinder or more generous offstage than vaudevillian Benny Kubelsky. But his slightly prickly streak gave radio star Jack Benny something to work with in creating his eponymous show about the vain, preening, penny-pinching 39-year-old egomaniac who went on to make TV history with a show that ran 15 years.

From George Burns to Larry David, orneriness has been handy in portraying “oneself.” Jerry Seinfeld — like Benny, a hilarious observer if indifferent actor — followed the pioneer’s lead in surrounding himself with wacky pals whose antics he could punctuate with wry asides. On that famous couch, Seinfeld found his sweet spot cracking wise about Nothing.

Apatow recalls, “On ‘The Larry Sanders Show,’ Dana Carvey used to call the character ‘Ga-larry,’ because some of it was Garry in real life and some the character he’d created.” Yet the former is “an observer of the human condition” as contrasted with Sanders, “an evil, maniacal host obsessed with being #1. … Very, very different people.”

Louis C.K.’s divorced veteran standup “Louie” falls squarely within the Benny/Seinfeld/Shandling tradition, though without benefit of sidekicks. His is essentially an anti-stock company, as exec producer Blair Breard says. “He has two different sisters … and his mother is played by two different people. It’s purely figments of his imagination.”

The smash FX skein fully exploits its star’s tri-furcated personality: edgy on stage; hapless in love; sympathetic in life. His whip-smart, raw presence at the Comedy Cellar mic contrasts sharply with his bumbling efforts to re-launch his romantic life in his “humane vignettes,” as Breard calls them.

She confesses, “Even my parents go, ‘I can’t take it, he’s much too raunchy.’ And I tell them to get through the standup, because when he leaves the club he’s gentler and quieter, and can be more bewildered by the situations he finds himself in.” Still and all, both personas differ from the Louis she works with, “a thoughtful and sensitive person” who “rarely if ever uses the kinds of expletives he throws around on the show.”

When a star’s temperament is grafted onto a “civilian” role, context is critical. Roseanne shone as a factory worker, and OB/GYN fits Mindy Kaling like a rubber glove on “The Mindy Project.” But one strains to recall the occupations of Drew Carey and Ellen DeGeneres on their eponymous vehicles. (Both eventually found greater success simply being themselves, Carey as host of the “The Price Is Right” and Ellen as talkshow doyenne.)

Kaling and her onscreen character Lahiri share “less overlap than most people think,” the star reports. “Our cadences are similar … and we both have given our lives over to the jobs we love.” But Dr. Lahiri “is a wildly confident character” with an “ability to bounce back from adversity. I am much more of a sensitive and prickly comedy writer.” (There’s that prickliness again.)

“The single biggest difference is that Mindy Lahiri is a flirt and unafraid of men, and has a limitless confidence in terms of her love life. I am much more shy and have pretty bad social anxiety.”

Strict lines are drawn on HBO’s “Girls” by Dunham, who “made it clear from the very beginning, this wouldn’t be ‘The Lena Dunham Show,’” according to exec prod and writing partner Jenni Konner.

“By calling her character ‘Hannah,’ she’s signaling there’s a distance between the character and herself, a level of fiction,” Konner says, which isn’t to say the star-creator-writer doesn’t pull from her everyday life. “Lena will experience something and almost immediately be able to process it, write it and get it into the show.”

To Apatow, “Lena is similar to Seth Rogen, as they both present themselves as being kind of a mess, when in real life they are very organized, work very hard and get a lot done. In the show she struggles to figure out what she wants to do, but in life it’s clear what her goals are.”

Michael J. Fox and Tracy Morgan’s goals are equally clear as they embark on new sitcom ventures. But can Morgan find his sweet spot as a pot dealer turned war hero? How amusingly will “Mike Henry,” a married dad and newsman with Parkinson’s, reflect Fox’s own family situation and medical adventures?

Stay tuned.