Buoyed by positive reviews for the South Bend mayor's performance at an hour-long CNN town hall earlier this month and a steady stream of well received appearances on TV, Buttigieg's 2020 presidential exploratory committee has felt a sustained surge of momentum over the past two weeks. The once little-known mayor is getting recognized across the country, while his committee has mapped out plans to double in size in the coming weeks as a steady stream of new donations flood to the 37-year-old Democrat.

It's been an eye-opening experience for Buttigieg, a mild-mannered candidate who seems allergic to bragging.

"It's heady," Buttigieg said in an interview with CNN. "And it has happened very quickly."

Buttigieg's fundraising still trails what is known about candidates like Sen. Bernie Sanders and former Rep. Beto O'Rourke, and he has yet to see a boost in national or state level polling, but the news has been welcomed by the mayor, who started the campaign with little to no national name recognition and significantly smaller crowds in key states.

"The good news is it means the more people that see our message, the more it resonates," he said. "Because what I said in the town hall is no different than what I've been saying all along, it's just that more people saw it."

Buttigieg said that he could tell -- on a personal level -- when he started to get noticed by people in restaurants and other places, but that he is fighting letting it go to his head.

South Bend Mayor Pete Buttigieg speaks Saturday during the Democratic monthly breakfast held at the Circle of Friends Community Center in Greenville, South Carolina. (AP Photo/Richard Shiro)

"That's good news but I'm trying not to let it go to my head because for every one person that stops me at the airport or on the street there's still probably 99 who still haven't heard our message yet," he said.

The momentum was apparent throughout Buttigieg's 24-hour swing through South Carolina, his first since launching his exploratory committee in January. In Greenville, Columbia and Rock Hill, Buttigieg spoke to packed rooms of voters, some of whom told the candidate that they had only learned about him a few weeks ago.

At an event for Tina Belge, the Democrat running in a special election for a state senate seat around Greenville, Buttigieg -- who initially stood out in the race because he is gay, hails from Republican Indiana and had a funny last name -- teased his newfound momentum.

"I get that my presence here is a little bit unlikely," he said. "(I get) that it is not customary for a millennial, Midwestern mayor to be in the conversation about the future of the free world."

He later told a packed venue in Columbia that "a month ago no one knew who I was."

And he joked in Rock Hill that he can sometimes "fool myself that I am really famous," before he realizes most people know nothing about his campaign.

Kate Franch, the chair of the Greenville County Democratic Party, told CNN that the excitement around his visit outpaced others they have hosted for 2020 Democrats.

"This is not our normal crowd," Franch said, looking around at the cafeteria at the Upstate Circle of Friends Community Center that she was filled twice as much as it normally has been. "When people heard he was coming, that is when a lot of people started reaching out (to attend today's event) ... There is a lot of excitement around him."

Part of that excitement comes from voters like Adi Dubash, 37, and Michael Upshaw, 34, a gay couple who brought their 16-month-old son Finnick to Buttigieg's Greenville event.

Pointing to his son, Upshaw said, "For me, with him now, I want him to grow up in a world where our leaders are representative. Right now, there is nothing in Washington that I am proud of for him to grow up in, but with a guy like Buttigieg, I can say, 'Your dads are represented. You are growing up in a world (that) accepts people and families like you are growing up in' and that means a lot to me."

In need of 'a more robust infrastructure'

The boom in attention has also meant wholesale changes to Buttigieg's campaign.

Mike Schmuhl, Buttigieg's campaign manager who has been the mayor's friend since the two met in ninth grade, said that the campaign is looking to double in size -- from twenty staffers to upwards of 40 -- in the near future and has rented a campaign headquarters in South Bend that is five times larger than the one the exploratory committee currently occupies.

Schmuhl said that when he and the team launched the committee, they banked on the possibility that a viral moment would vault them into the conversation and that his team just had to be ready to capture that momentum.

"In the early stages of this exploratory effort, we've been organizing our team to capitalize on critical moments to build more enthusiasm — like the CNN Town Hall — and ultimately a more robust infrastructure," Schmuhl said.

It appears that they have: According to Lis Smith, Buttigieg's spokeswoman, the committee raised more than $600,000 in the first 24 hours after the CNN town hall. When the campaign followed up that fundraising with a call for $500,000 in donations before March 31, they raised it in 24 hours, Smith said. When they asked for the same pledge two days later, they raised another $500,000, bringing their haul from those two emails alone to more than $1 million, she added.

And when the short-staffed committee put out a call for resumes, they received more than 2,000, according to Smith.

The surge in support, while welcome news for the Buttigieg team, also comes with pitfalls. The mayor said he worried about securing the necessary staff to capture the attention, while others around him pushed to raise as much money before the end of the first fundraising quarter, something Buttigieg has tried to do with fundraisers in California, Illinois and New York.

Those concerns were echoed by David Axelrod, a former senior adviser to President Barack Obama and Buttigieg friend, who said "the challenge for any startup campaign that gets some tailwind is how to catch up to their own momentum."

"How do you capture the data and build relationships with all the people suddenly eager to help? How do you quickly build an organization equipped to utilize that data and those relationships and develop a strategy, particularly in the must-win early states," said Axelrod, who is a CNN senior political commentator. "And how do you prepare for the sterner tests that come for a 'hot' candidate, as media and opponents begin to poke and prod with greater intensity to see if you are up to the job."

He added, "It's challenging."

Reflections on faith resonate on the trail

Buttigieg's rise has rhetorically been based on two major applause lines on the campaign trail: His attacks on Mike Pence and his discussion of his faith, particularly how it relates to his marriage to Chasten Buttigieg, a teacher he married less than a year ago.

"My former governor (Vice President Mike Pence) is going to be visiting your state soon," Buttigieg said to a chorus of boos in Greenville. "I think you already know how I feel. It helps me empathize with you on that whole Lindsey Graham thing," he added to even louder hisses.

The line mimics an attack the mayor lobbed during the CNN town hall, where he questioned Pence's faith by rhetorically asking how Pence could become "the cheerleader for the porn star presidency."

"Is it that he stopped believing in scripture when he started believing Donald Trump," Buttigieg said in a line that quickly reverberated among Democrats.

Buttigieg has been upfront about faith, talking openly about his Episcopal beliefs and why he believes Democrats need to embrace religion.

"So much of what Christ's teachings are about have to do with the way that we take care of the least among us," said Buttigieg recently. "I think for those of us who think that our morality is something that needs to be in touch with our religious faith personally, then it's really important to explain that no one party has a monopoly on faith."

The mayor combined his lines on Pence and his talk of faith later in his speech in Columbia when he spoke about his marriage, describing it as something "that has made me safer and better and, yes Mr. Vice President, has moved me nearer to God."

'I am going to follow him on Twitter!'

Buttigieg, who came out in 2015, also used his marriage to show how much politics matter, telling the audience in Columbia that the fact that he was legally allowed to marry Chasten Buttigieg in 2018 was something going for him when both of his parents were recently ill (his father died shortly after he announced his exploratory committee).

"He is an amazing human being, who when I was getting in the car to make that drive, was in the hospital with my priest and with my mother because he could get into the hospital because he was a member of my family," Buttigieg said, "a fact that exists as a matter of law by the grace of a single vote on the Supreme Court."

The audience erupted in response, something that seemed to surprise Buttigieg himself.

Responses like that explain why Chasten Buttigieg has become a minor Twitter celebrity, whose following on the social media platform has multiplied by more than a factor of six since the start of March. The platform has even led Chasten Buttigieg -- whose husband described him to a Democrat on Saturday as "a great asset" and someone who is "very outgoing" and "very warm" -- to take a leave of absence from his teaching job as he focused on the campaign.

And that fame has transferred into the real world, too.

Chasten Buttigieg was at his local Costco recently when someone walked up to him with a question.

"Hey," said the shopper. "I've seen you on Twitter. Aren't you someone's husband or something?"

Tania Meneses, a 47-year-old from Greer, South Carolina, encapsulated the supporter Buttigieg has captured in recent weeks. The Democrat who was born in Nicaragua had never heard of Buttigieg until recently, but when she came out to see him speak on Saturday, she was giddy with excitement afterward.

"I only learned about him through this event. It's a shame because he has such great potential," she said. "We need his kind of face in our party."

When asked if she is going to keep in touch with him after he leaves, she smiled and exclaimed, "I am going to follow him on Twitter!"