As top-tier presidential candidates go, Ron DeSantis is something of a rarity these days. He was born after the Vietnam War, he came of age when computers were common in American homes and he still has young children of his own, rather than enough grandchildren to fill a basketball team.

Mr. DeSantis would be 46 on Inauguration Day if elected, younger than every president since John F. Kennedy. It’s a fact he doesn’t state explicitly, but his campaign has set out to make sure voters get it.

The Florida governor talks frequently about having the “energy and discipline” needed for the White House, keeping a busy schedule of morning and evening events. He and his wife, Casey DeSantis, often speak about their young children, who are 6, 5 and 3 and have joined their parents on the campaign trail. One of the few candidates with kids still at home, Mr. DeSantis regularly highlights his parental worries about schools and popular culture as he presses his right-wing social agenda.

When he signed the state budget on Thursday, he joked that a tax break on one of parenthood’s most staggering expenses — diapers — had come too late for his family, though not by much.

“I came home, and my wife’s like, ‘Why didn’t you do that in 2019 when our kids were still in diapers?’” Mr. DeSantis said.

The evident goal is to draw a stark contrast with his main rivals, President Biden, 80, and former President Donald J. Trump, who just turned 77, both grandfathers who have sons (Hunter and Don Jr.) older than Mr. DeSantis. Voters have expressed concern about the age and fitness of both men, especially Mr. Biden.

Roughly two-thirds of registered voters believe Mr. Biden is too old to effectively serve another four-year term as president, according to a national poll conducted by Quinnipiac University last month. Only 36 percent of registered voters said the same of Mr. Trump, suggesting that Mr. DeSantis’s relative youth might be more of an advantage in a general election than in the primaries.

Still, Mr. DeSantis, 44, rarely talks directly about his age, and the party he represents — older and whiter than the country at large — has never been known for nominating young presidential candidates who ride a wave of energy to the White House, as Kennedy, Bill Clinton and Barack Obama did.

His conservative views on abortion, climate change and how race is taught — among other issues — have left Mr. DeSantis out of step with many members of his own generation. Majorities of voters in his age bracket want abortion to be legal in all or most cases, think climate change is a very serious problem and support the Black Lives Matter movement. Only about one in four voters between the ages of 35 and 49 have a favorable view of Mr. DeSantis, according to the Quinnipiac poll.

Mr. DeSantis also hardly seems to have a natural knack for capturing youthful enthusiasm in the way that Mr. Obama did. The last major candidate to run on a platform of generational change, the 44th president was able to count on the support of young and influential cultural icons, including hip-hop artists.

Other than railing against “wokeness,” Mr. DeSantis scarcely mentions cultural influences like television shows, movies, music or social media. One of his attempts to reach younger people — announcing his campaign on Twitter with Elon Musk — went haywire when the livestream repeatedly glitched out. His rally soundtrack is a generic mix of country and classic rock, augmented by a DeSantis tribute anthem to the tune of “Sweet Home Alabama.” He doesn’t talk much about his love of golf or discuss his hobbies. His references to parenthood are often prompted by his wife.

But his children — Madison, Mason and Mamie — are highly visible. Neat stacks of toys, including baseball bats and a bucket of baseballs, are usually arrayed on the front porch of the governor’s mansion in Tallahassee, visitors say.

No presidential family has raised children as young as the DeSantis brood since the Kennedys, prompting hopes among supporters of a conservative Camelot at the White House. The comparison is one Ms. DeSantis especially seems to be leaning into. The elegant gowns and white gloves she sometimes favors have seemed to evoke the wardrobe of Jacqueline Kennedy.

The couple’s family-centric image has softened views of Mr. DeSantis among some Democrats in Florida. “I don’t like him as a politician,” Janie Jackson, 52, a Democratic voter from Miami who runs a housekeeping business, said in an interview this past week. “But I think he’s a good father and husband.”

Mr. Trump, who is twice divorced and has five children with three different women, could be particularly vulnerable to such comparisons.

“Engaging with his family helps humanize him,” Dave Carney, a New Hampshire-based Republican strategist, said of Mr. DeSantis. “He’s a dad. People can relate to that. It gives him credibility to talk about family issues.”

But voters can sniff out shtick, Mr. Carney added. “There’s a balance,” he said. “You don’t want your kids to seem like a prop.”

Younger Republicans do seem to be responding to Mr. DeSantis. A recent poll by The Economist and YouGov found that the governor received his highest level of support from Republicans and Republican leaners aged 18 to 29, although he was still trailing Mr. Trump by 39 percent to 27 percent in that group.

At almost every stop on their swings through the early nominating states, Mr. DeSantis and Ms. DeSantis, who often joins her husband onstage to deliver her own remarks, mention their young family.

On a recent trip to Iowa, Mr. DeSantis and his wife, 42, arrived at the state fairgrounds with their children in tow. All three were wearing DeSantis-branded shirts with a “Top Gov” logo on the back. They signed a bus belonging to a pro-DeSantis super PAC — his son did so while wearing a baseball glove — as Ms. DeSantis, sporting a black leather “Where Woke Goes to Die” jacket despite the heat, knelt down to help. Their eldest, Madison, wrote her name in red and drew a heart above it.

“Did you guys write your stuff on there?” Mr. DeSantis asked, after wading through attendees while lifting up one daughter. The kids then moved on to an ice cream giveaway organized by the super PAC.

“Want me to hold you?” Mr. DeSantis asked his son, Mason, before picking him up as the boy continued to eat ice cream.

On the stump, Mr. DeSantis usually talks about his children to emphasize policy points, particularly on education, or to accentuate his long-running feud with Disney, which he accuses of indoctrinating children.

“My wife and I just believe that kids should be able to go to school, watch cartoons, just be kids, without having some agenda shoved down their throats,” Mr. DeSantis said on a visit to New Hampshire. “So we take that very seriously, and we’ve done an awful lot to be able to support parents.”

Mr. DeSantis’s approach to family issues appeals specifically to conservative Republicans and has been criticized by Democrats and civil rights activists. He has signed legislation banning abortions after six weeks, outlawing gender-transition care for minors, imposing punishments on businesses that allow children to see performances like drag shows and further limiting instruction on sexual orientation and gender identity in schools.

On the campaign trail, the DeSantises often try to temper the polarizing nature of his political persona with tales of family life.

Ms. DeSantis usually coaxes her husband to open up about their kids, including his adventures taking them for fast food at a restaurant populated by inebriated college students and, in a sign of the couple’s religiosity, having them baptized with water from the Sea of Galilee in Israel.

At one stop in New Hampshire, Ms. DeSantis apologized to the crowd for her raspy voice, suggesting she had strained her vocal cords in an effort to protect the furniture in the governor’s mansion from one of her daughters.

“I had a very long, in-depth conversation with that 3-year-old as to why she cannot color on the dining room table with permanent markers,” she said.

Now, Mr. DeSantis has competition from another youthful, if far less known, candidate from his home state: Mayor Francis Suarez of Miami, 45, whose campaign announcement video this past week shows him jogging through the city and mentioning his children.

Another lesser-known rival, Vivek Ramaswamy, has promoted himself as the first millennial to run for president as a Republican. Mr. Ramaswamy, 37, also has young children, sons ages 11 months and 3 years who have joined him on the trail. Campaigning with kids sometimes requires special accommodations, Mr. Ramaswamy said in a recent interview. His campaign bus, for instance, features two car seats and a diaper-changing table.

At the end of an event in New Hampshire this month, he turned away from the crowd to thank his older son, Karthik, for behaving so well during his speech.

“He got a bigger round of applause than I did,” Mr. Ramaswamy recounted.

Shane Goldmacher contributed reporting from Des Moines.