Welcome to the Podcast. First, a Word From Our Celebrity.

Katie Couric gets a great night’s sleep on the Casper mattress she and her husband, John Molner, share, and sipping Dunkin’ Donuts coconut coffee makes her feel as if she is vacationing in the islands. At holiday time, Ms. Couric is thrilled to receive a package of Omaha Steaks as a gift.

Listeners of “Katie Couric,” Ms. Couric’s podcast, already know these tidbits. Before diving into interviews with newsmakers and celebrities like Julia Louis-Dreyfus, Samantha Bee and the journalist David Fahrenthold, Ms. Couric and her co-host, Brian Goldsmith, banter about brands sponsoring the show, adding their personal endorsements.

A podcast hosting gig has become a new status symbol for top journalists, entertainers and talking-head politicos. Hosts can discuss whatever they want, usually for a rapt audience of in-car drivers and on-train commuters. Most podcasts are available free on iTunes, and advertising is often necessary to cover productions costs. So A-list talent is now singing for its soup, routinely peddling products like audiobooks, bedsheets and delivery meal services.

“Selling underwear on a podcast was always my highest aspiration,” said Jon Favreau, a former speechwriter for President Barack Obama who now is a host of “Pod Save America,” a political program. Mr. Favreau said he and the podcast’s other hosts, including his fellow former Obama staff members Jon Lovett, Tommy Vietor and Dan Pfieffer, look for topical and comical transitions that will lead them from discussing policy to reading ads.

“We really had some fun when Spicer did his first briefing and his suits weren’t fitting,” Mr. Favreau said, referring to the current White House press secretary, Sean Spicer. “We did an Indochino suit segue that worked really well.” When they needed to plug the payment application Square Cash, Mr. Pfeiffer quipped, “How else would I get my Soros cash?”

The practice of podcast hosts reciting advertisements is reminiscent of the early days of radio and television. There was “The Pepsodent Show Starring Bob Hope,’’ which promoted toothpaste, and NBC’s “Camel News Caravan,” with the journalist John Cameron Swayze mentioning the brand’s cigarettes. Ed McMahon pitched Alpo dog food on the “The Tonight Show Starring Johnny Carson,” often to hilarious results.

For today’s podcast announcers, it’s a return to the good old days. “It feels very retro in a kind of nice way,” Malcolm Gladwell, the author and New Yorker writer, said in an interview.

But the lofty rhetoric of some podcasts makes the sometimes lowbrow nature of the ads feel at odds with the show. During the first season of Mr. Gladwell’s podcast, “Revisionist History,” released last year, he reported on educational philanthropy and a 1960s Pentagon mission to interview North Vietnamese soldiers, among other subjects. On the finale episode, Mr. Gladwell summarized the central lesson that ties together the different episodes: “Nothing of consequence gets accomplished without courage,” he said.

But before anything of consequence gets accomplished on Mr. Gladwell’s podcast … first, a word from our sponsor. “First Republic is a bank with no teller lines,” Mr. Gladwell has told his listeners in a reassuring, singsong voice. “But they didn’t replace their tellers with computers or robots. How’s that possible? Personal bankers.”

The “Blink” author doesn’t dwell on the copy. “They send me the script, and I read it,” he said.

For Ms. Couric and Mr. Goldsmith, who worked together at CBS News, reading advertisements is a fresh challenge. “It’s clearly a new experience for both us, and we’re kind of being self-deprecating more than anything else about our lack of experience as marketers,” Mr. Goldsmith said.

“Katie and I have both gotten into doing the Princess Cruises ads,” he continued. “I personally have never been on a Princess Cruise. I honestly don’t know if Katie has been on the Princess Cruise.” So, they banter about the benefits of vacationing. “I think you need to have more experiences of awe, Brian,” Ms. Couric said in one episode.

Many of these hosts understand that “ad readers,” as they’re known, are economic necessities in funding passion projects, even if they would not be likely to flop down on a mattress in a television commercial. “In order for us to give away this free product, we have to do a little business on the other end,” said the actor Joshua Malina, who hosts “The West Wing Weekly” podcast with Hrishikesh Hirway. Their podcast takes a fine-tooth comb to each episode of political drama “The West Wing,” which had its series finale in 2006. (Mr. Malina was a “West Wing” cast member, and now has a prominent role as the attorney general on ABC’s “Scandal.”)

When they are not debating the skill the fictional press secretary C. J. Cregg shows in handling the news media, or which guest stars best handled the fast-paced dialogue, Mr. Malina and Mr. Hirway discuss the benefits of snacking with Naturebox. (“You’ve got to try the Sriracha cashews,” Mr. Malina said. “They will rock your world.” )

A recent “West Wing Weekly” focused on staff discontent after the fictitious President Bartlet misled the public, and featured a plug for a jobs website: “When I was looking for a co-host for ‘The West Wing Weekly,’ I used ZipRecruiter to find Joshua (Hotpants) Malina,” Mr. Hirway said. Mr. Malina responded, “And there were no other applicants.”

“One way or another, I’m involved in selling products,” said Mr. Malina, describing commercials that run during his TV shows. “This is cutting out the middleman — I’m selling you soap. It’s unlike what I usually do, which is sell soap by acting like I’m the attorney general of the United States.”

Podcasts are well suited for companies that otherwise couldn’t afford such a wide range of celebrity endorsements. Blue Apron is a particularly active podcast advertiser, with spots appearing on hundreds of podcasts, including “The West Wing Weekly,” said Jared Cluff, the company’s chief marketing officer. Though Mr. Cluff said the brand didn’t necessarily set out to market its service with celebrities, he agreed that podcasts were providing a comparably inexpensive way to do so. How many start-up meal-delivery companies can get Alec Baldwin to read their menus aloud in his deep, recognizable voice? That’s precisely what Mr. Baldwin does for Blue Apron on his podcast, “Here’s the Thing.”

“He definitely romances our ingredients,” Mr. Cluff said.

Lena Dunham has made an effort to personalize the Blue Apron ads on her popular podcast, “Women of the Hour,” even though she doesn’t actually use the product. She is particularly proud, she wrote in an email interview, of her practice of including her mother, the artist Laurie Simmons, in the Blue Apron spots. Ms. Dunham started doing so after Ms. Simmons complained to her about the lack of enthusiasm conveyed in podcast ad reads.

In one such take, Ms. Dunham asked her mother if she recalled “that brief phase” when she frequently cooked for the family. To this Ms. Simmons gamely retorted, “I think Blue Apron would have been really helpful when you were growing up.”

Brian Koppelman, a creator of the Showtime drama “Billions,” has an enthusiastic interview style for his podcast, “The Moment,” for which he interviews famous authors, actors and other artists about their creative process. In a recent interview, Mr. Koppelman praised the celebrity chef Marcus Samuelsson for studying Miles Davis in his effort to maintain an original viewpoint in the kitchen.

Mr. Koppelman weaves in the same exuberance and personalization when he feels a connection to the product, like his two-minute tale about his teenage self impressing a crush by talking his way into getting them free doughnuts. “I don’t know if it was the doughnuts, but the girl kissed me,” he said, “and I’ve been a Dunkin’ Donuts fan ever since.”

Mr. Koppelman and his fellow podcasters get a kick out of hearing other podcast hosts put their personal spin on what would otherwise be ho-hum ad copy. And they say they also see the humor listeners might find in it.

“It’s a funny thing having a person you know from all these other areas of life reading ads,” Mr. Favreau said, adding that he and Mr. Lovett drafted a skit for Mr. Obama’s final White House Correspondents’ Association dinner, in 2016, portraying a post-presidency Mr. Obama as a podcast host, a gig requiring him to reading Stamps.com ads. The idea for filming the skit was scrapped.

“They decided it might not be the best use of the president’s time,” Mr. Favreau said.