Julia Louis-Dreyfus was not feeling relaxed. In a few weeks, she would be receiving the Mark Twain Prize for American Humor, in a televised ceremony at the Kennedy Center, and she was anxious about her speech. “It’s, like, ‘If you’re so fucking funny, get up onstage and prove it!’ ” she said one morning in Los Angeles. She was sitting in a white bathrobe, having her makeup done, in a room at the Glendale Hilton, where she was shooting an episode of her HBO series, “Veep.” Louis-Dreyfus has nine Screen Actors Guild Awards and a Golden Globe, and she shares with Cloris Leachman the record for the most Emmys accumulated by an actor: one for playing Elaine Benes, on “Seinfeld,” the role that made her a star; one for her performance in “The New Adventures of Old Christine”; and six for playing Selina Meyer, on “Veep.” But the Twain prize felt different. “Anyone can bomb,” she muttered. “Oh, God. Whatever.”

When the makeup was finished, a stylist ran a curling iron through Louis-Dreyfus’s shiny brown bob, one of several wigs she’s worn while making “Veep,” in order to minimize her preparation time. Her real hair is explosively curly, when it hasn’t been coaxed into sleekness for an event. These days, it is also “blasted by chemotherapy and still growing out,” after six rounds of treatment that Louis-Dreyfus underwent last year for breast cancer. She’d decided to address her illness and recovery at the Twain prize, but, as she put it, “I don’t want it to be ‘The Cancer Show at the Kennedy Center.’ ”

Later that day, she sat with the showrunner of “Veep,” David Mandel, in a small conference room in the Hilton, surrounded by a dozen writers and assistants, who were helping Louis-Dreyfus fine-tune her speech over lunch. (Mountains of dumplings from Din Tai Fung for the writers, and a spinach salad for Louis-Dreyfus, which her assistant handed her in a Tupperware. Asked how it was, she replied, “Punitive.”) She leafed through a printout of the speech. “O.K., should we hear this thing and see how bad it is?” she asked, and began to read. “ ‘When Mark Twain first e-mailed me about the prize, I totally misunderstood: I assumed that I was being asked to honor somebody else, and I thought, Oh, my God, what a hassle. I have to go all the way to Washington, D.C.—which, no offense, is a nightmare—and get a dress and all that crap, and make up flowery things to say about how funny someone else is? No effing way.’ ” The writers tittered. “ ‘Then I reread the e-mail and I realized—it’s me! They’re giving it to me! And I get the prize! And my attitude about the whole thing changed, it really did.’ ”

In the section of thank-yous, the speech turned fractionally more serious, and Louis-Dreyfus wound her way toward her health. “ ‘The old cliché about laughter being the best medicine turns out to be true: when I was getting my hideous chemotherapy, I’d cram a bunch of friends and family into the tiny treatment room with me . . .’ Gosh, as I’m saying this I’m going to cry,” she said, and started to. She shook her head in self-rebuke, then continued, “ ‘We really did have some great laughs. Of course, I was heavily medicated and slipping in and out of consciousness, so I was a pretty easy audience.’ ” She wiped her eyes. “ ‘My point is that laughter is a basic human need along with’—oh, fuck!” she said, crying harder but also sort of laughing, “ ‘along with love, and an HBO subscription.’ That would have worked better if I weren’t weeping.”

After the shoot that day, Louis-Dreyfus described her recent state of mind. “You know if you get on a horse and you have really tight reins and the horse is galloping?” she said. “I felt like I had really tight reins on myself. That’s what it felt like: I was just holding on tight.” Then she rolled her eyes and said, “I’ve had a really rough year, blah, blah, blah—you know, we’re getting through it.” She thought about it for a second. “I had a rough couple of years, actually.”

In the fall of 2016, on the Friday before the Emmys, Louis-Dreyfus’s father died. She won the award, and during her acceptance speech her voice cracked as she dedicated it to his memory. “I’m so glad that he liked ‘Veep,’ ” she managed, “because his opinion was the one that really mattered.”

A year later, on the Friday before the 2017 Emmys, Louis-Dreyfus went to see a radiologist about a lump she had noticed in her breast. “He did a biopsy,” she recalled, “and he said, ‘I think you should prepare yourself for bad news.’ ” That Sunday, she won her sixth Emmy for “Veep,” setting a record for the most wins by an actor for a single role. “Monday morning, I found out—it’s cancer,” Louis-Dreyfus said. “I mean, is that crazy?” She gave a little half laugh, half snort. “So I was glad to give the Emmys a skip this year,” while her show went on hiatus as she did chemo.

“I have a different kind of view of my life now, having seen that edge—that we’re all going to see at some point, and which, really, as a mortal person you don’t allow yourself to consider, ever. And why would you? What are you going to do with it?” she concluded. “I was a little more breezy before. I was a little . . . breezy.”

If there was one move that expressed the essence of Elaine—uninhibited, emphatic, irrepressible—it was the shove. When she was outraged or shocked or dazzled, she put her hands on the chest of the man who was eliciting that reaction, shouted, “Shut up! ” or “Get out!,” and then shoved him so hard that he toppled backward. It was a kind of kid-sister move, at once obnoxious and irresistible—a way of propelling another, bigger person into her reality.

It was a move that Louis-Dreyfus brought to Elaine, but it predated the character by at least a decade. “The way that she would shove guys—that’s the way she had to treat us,” Paul Barrosse, who cast Louis-Dreyfus in a comedy show when they were students at Northwestern University, said. “That kind of physicality was on display very early.”

Louis-Dreyfus was a freshman and Barrosse was a senior when she joined the “Mee-Ow Show,” which she describes as “the comedy show on campus.” She told me, “It was the seminal moment in my life. I remember thinking, Oh, this feels like something huge. And it was something huge: everything came from that.”

At eighteen, Louis-Dreyfus was already strikingly self-assured. “There’d be, like, seven male cast members and two female,” Barrosse said. “I and some of the other senior guys in that show were like the eight-hundred-pound gorillas in the room, with huge egos, and she really stood up to that. I remember she was working on a scene with someone, and we came poking our noses in, and she threw us out of the room: ‘What are you doing? We’re trying to work in here!’ ”