Colin Jost seems like a bundle of nerves.

By all accounts, including his own, he’s enjoyed tremendous success at a relatively young age. The 38-year-old’s new memoir, "A Very Punchable Face" (Crown, $27), traces his life thus far, from his childhood in Staten Island to writing for the Harvard Lampoon to his 15-year stint as part of "Saturday Night Live," where he’s a head writer and co-anchor of the "Weekend Update" segment.

He’s co-hosted the Emmys, fought at WrestleMania and successfully proposed to Scarlett Johansson.

But he was also, as he shares in the assortment of essays that comprise "Face," a "fat" kid who didn’t start speaking until he was 4, and a champion overthinker.

"I’m not a person who opens up easily," Jost writes in the introduction. "That’s why I rarely post anything on social media or do any serious interviews. I feel ashamed when talking about myself even though everyone is doing it." Nevertheless, he’ll have to do so on Thursday, when best-selling novelist John Grisham interviews him virtually via BookPeople.

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Explaining himself on the page is far easier, he notes. And as the title of his book signals, he’s the first to poke fun at himself. He includes a picture as a chubby 10-year-old swimmer during a brief stint as an athlete before joining the "chastity belt" speech and debate team, where he started to hone his rudimentary comic skills. "My friends and I spent half our time recreating the cheesy performances from other schools, which was so much more fun than earnestly doing our own pieces," he recalls.

Studiousness paid off with a berth at Harvard, where he honed in on a singular obsession: get a piece published in the Lampoon, the university’s legendary humor magazine. It’s a work style that served his career well (if not his psyche) once he embraced standup and comedy writing.

There are certainly funny bits from the early part of the book — highlights include his brushes with semi-greatness like the Winklevoss twins and an ill-fated study abroad trip to Russia — but fans will no doubt most enjoy his behind-the-scenes tales from "SNL."

Jost recaps the backstory behind some of his favorite sketches, including the 2018 cold open with Matt Damon satirizing then-nominee Brett Kavanaugh’s Supreme Court confirmation hearing meltdown. Jost and team wrote the sketch on a Friday. Damon agreed after midnight to do it, script unseen, and then got on a plane. He "landed in New York Saturday morning, slept for about forty-five minutes, drank one beer to get into character, and delivered an incredible performance."

One of the funniest essays showcases the notes received from network censors. Virtually none are printable. One that is: "Let’s discuss ‘toilet babies.’" And he observes that some of the host/musical guest pairings double as time capsules: "It’s like joke combinations you would see on a ‘Family Guy’ parody of ‘SNL’: Charlton Heston and Wynton Marsalis. John Larroquette and Timbuk 3. Sylvester Stallone and Jamiroquai."

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Throughout the book, Jost’s anxiety frequently is on display. He has panic attacks and heart palpitations, and his initial shows behind the "Weekend Update" anchor desk tanked: "If I had a Yelp page, it would be a thousand 1-star all-caps tirades with the words ‘Closed Permanently’ under my name."

By design, the book’s structure is a David Sedaris-like compilation of essays that work as a whole but also stand individually. Yet the one that truly stands out isn’t funny at all. It’s the story of his mother’s experiences on 9/11 as a first responder. It’s by turns terrifying, honest and tender, and almost seems to belong to another book entirely. Jost was a college sophomore, and for hours he didn’t know where his mother was.

Save for a callback to fellow "SNL" cast member Pete Davidson, whose firefighter father died that day, the essay is a lovely ode from a son to his mother. It would undoubtedly get five stars on Yelp.