About every four years, Steve Kornacki becomes a reluctant internet celebrity.

The comedian Leslie Jones has called him “the sexiest nerd on TV.” People magazine agrees. His go-to outfit — glasses, a white dress shirt, a tie and khaki or dark pants — is a trendy Halloween costume in some Washington circles.

“I’m not sure I really understand it, but I’m flattered,” said Kornacki, a national political correspondent for NBC News who becomes an object of desire during election cycles for his adroitness with a large touch screen and his analysis of electoral maps and polling data.

At one point in November, Kornacki spent about 17 consecutive hours on air. That was a cakewalk compared with 2020, when the presidential election was not called for four days. He slept a total of 10 hours that week with a couple of naps at his desk.

After that exhausting stretch, NBC Sports asked Kornacki whether he would bring his data presentation skills to “Football Night in America,” its Sunday night studio show, to dissect the playoff chances of National Football League teams. Kornacki, who grew up in Massachusetts as a New England Patriots and Boston Celtics fan, accepted the additional responsibilities, saying he would have been watching football anyway.

Similar to election night, when Kornacki explains which states could enable a candidate to reach 270 electoral college votes, his football segments untangle the best paths forward, including the must-win games for teams still mathematically alive in the playoff hunt.

The permutations can get complicated. The Los Angeles Rams clinched their division last weekend because of a strength of victory tiebreaker — the combined record of the 10 teams they have defeated so far.

“We’re looking at scenarios, we’re looking at variables, we’re looking at probabilities and that’s exactly what I’m doing for a campaign,” Kornacki said.

Kornacki graduated from Boston University and worked at various outlets before co-hosting an MSNBC show in 2012. He became a mainstay for election coverage in 2014, but his social media stardom came in 2020, when viewers flocked to televisions for an important election during the coronavirus pandemic.

Kornacki said the coverage most likely resonated because he and the viewers were absorbing the onslaught of information together.

“It’s a really shared experience where I’m seeing things on the screen for the first time, and they’re seeing something on the screen for the first time,” he said.

Kornacki prepares for an election throughout the year, but the process intensifies about six months out. It is particularly important, he said, to study demographic data in battleground states and counties. He uses spreadsheets and maps to memorize the information so he can immediately recall it on television when discussing voting patterns.

Kristen Welker, who anchors “Meet the Press,” NBC’s Sunday morning public affairs show, said she was impressed during a segment in October when Kornacki outlined how Democrats in Pennsylvania had lost support between the 2012 and 2020 elections in some counties with growing Latino populations. Donald J. Trump, the Republican nominee, won the coveted swing state weeks later.

“In many ways, he holds up a mirror to the country to say, ‘This is who we are right now and this is where we’re headed,’” said Welker, who in 2020 moderated a presidential debate.

Political enthusiasts and die-hard sports fans may seem to have little overlap, but they are both passionate television audiences.

“It’s kind of hard to ignore,” Kornacki said. “On a very basic level, these are both contests that are going to have a winner at the end of the day, and the winner is the product of the numbers that go into it.”

Kornacki’s duties in Stamford, Conn., where NBC Sports is based, are much easier than his time parsing elections in 30 Rockefeller Plaza. Pro Football Focus, an analytical company, supplies the network with myriad projections of the N.F.L. teams fighting for 14 playoff berths. The final seeds in the bracket are often undecided until the regular season’s final weeks, and can hinge on winning percentages and tiebreaking formulas.

Sometimes the analysis is straightforward: Whichever team wins the matchup between the Detroit Lions and the Minnesota Vikings on Sunday night, which airs on NBC, will earn the conference’s top playoff seed.

In additional to his football work, Kornacki has also contributed analysis on NBC Sports about the Olympics, the Kentucky Derby and even the National Dog Show. NBC will begin airing National Basketball Association games next season, but Kornacki said he had not heard if he would be involved.

Sports have been an enjoyable escape outlet, but Kornacki’s day job is still politics.

This fall, he asked to work the Breeders’ Cup, a marquee horse race event held in Del Mar, Calif. But the presidential election was a few days away, and network executives wanted him fresh. There were maps to decipher.