(CNN) Pete Buttigieg will headline a series of top-dollar, celebrity laden fundraisers across California this week, the latest sign that his rise in the polls has opened the doors -- and the wallets -- of donors who had previously dismissed the South Bend, Indiana, mayor's once-quixotic campaign .

In total, Buttigieg will headline more than ten fundraisers in California from Wednesday to Friday, according to invites obtained by CNN, picking up checks from Hollywood celebrities like Gwyneth Paltrow and Bradley Whitford, top tech investors and CEOs in Silicon Valley and a top fundraiser for President Barack Obama in the San Diego area.

Although Buttigieg has been furiously fundraising throughout much of 2019, the trip to California represents Buttigieg's most sustained and jam-packed fundraising swing to date, a reflection that his rise in prominence and popularity has turned into acceptance among top donors who fueled the campaigns of Obama and 2016 Democratic nominee Hillary Clinton.

"His trajectory is unlike anything I've seen in politics," John Atkinson, a Chicago insurance executive, told CNN. Atkinson was a bundler for Obama's campaign and now is raising money for Buttigieg. "When I reach out and talk to people, first of all, they know who he is. And very significant donors and people who are activists in the party are interested in finding out more."

The insurance executive will co-host a May 16 fundraiser for Buttigieg in Chicago with other ex-Obama bundlers.

Buttigieg raised more than $7 million in the first quarter of 2019, an unexpected haul for a candidate who admits that he thought he was going to spend the first three months of the year telling people how to pronounce his Maltese last name.

"I think I've gone from being viewed as, you know, adorable six weeks ago to now plausible," he told CNN in April.

And a Buttigieg campaign aide said the trip across the state shows the mayor plans on working hard to win the state, despite how costly competing in California can be to less-funded campaigns.

Buttigieg will arrive in San Diego on Wednesday and will immediately hit a top-dollar cocktail party and dinner hosted by Christine Forester, a La Jolla businesswoman who was a vice chair of Obama's national finance committee in 2008. She was one of Obama's top bundlers in 2008.

Buttigieg will next travel to Los Angeles on Thursday, where he will headline at least five fundraisers, including one event hosted by Academy Award-winning actress Gwyneth Paltrow and West Wing star Bradley Whitford.

Buttigieg will start the day with a top-dollar breakfast fundraiser hosted by Marc Bodnick, an entrepreneur and the founder of Elevation Partners, and his wife Michelle Sandberg, the sister of Facebook's Sheryl Sandberg; Hollywood producer Jordan Horowitz, known for his work on La La Land; and Vicki Kennedy, who is married to former presidential candidate Robert F. Kennedy's son, Max.

Buttigieg will then head to a lunch fundraiser in Brentwood hosted by an array of Democratic donors and afterwards head to a large, so-called "grassroots" fundraiser, where lower ticket prices -- entrance starts at $25 -- allows more supporters to attend. The event will be hosted by film director Samuel Greisman, whose mother is Sally Field, and West Hollywood Councilwoman Lindsey P. Horvath, among others.

Buttigieg's full day in Los Angeles ends with two high-dollar fundraisers: one in Beverley Hills hosted by Claire and Brian Goldsmith and the event hosted by Paltrow and Whitford.

On Friday, Buttigieg heads to San Francisco for at least four events hosted by a slew of Silicon Valley investors and executives.

His day starts with an afternoon fundraiser hosted executive from LiveRamp, a technology and data company based in San Francisco, including CEO Scott Howe.

Buttigieg then heads to an afternoon fundraiser hosted again by Bodnick and Sandberg, as well as Charlie Cheever, the co-founder of Quora and a former engineer at Facebook, and another grassroots event in San Francisco where tickets start at $25.

Buttigieg finishes his fundraising swing with a final high dollar event hosted by Isaac Pritzker, Adam Hundt and Ben Schwartz. Pritzker is a scion of the wealthy family with roots in Chicago that made its fortune in real estate and the Hyatt hotel chain

Despite the frenetic push for money, the South Bend mayor is a somewhat reluctant fundraiser. At an event in South Carolina on Monday, Buttigieg described how former President Jimmy Carter's famously shoestring general election campaign against President Gerald Ford in 1976 relied on post-Watergate changes to the Federal Election Campaign Act that allowed presidential campaigns to receive up to $20 million in public money in the general election as long as they raised no private money.

"I think a lot of the candidates would enjoy living in a world where you wouldn't have to do a lot of fundraising," Buttigieg said -- prefacing the comment with how much he appreciates those who have given to his campaign.

Opening donor doors

Buttigieg's rise in popularity has seen donors -- some of whom have locked onto one or two other candidates -- give the little-known South Bend mayor a shot.

The clearest sign of that is Susie Tompkins Buell, a top Clinton donor who backed her home state senator -- Kamala Harris -- early in the 2020 race. Buell was impressed by Buttigieg after seeing him, though, and hosted a 150-person fundraiser for the mayor in April at her home in the Bay Area.

"He is very authentic, and this is what people are craving," she said. "That is one thing he has in common with the current president -- what you see is what you get."

"Otherwise," she concluded, "they are complete opposites."

Longtime Clinton donor Robert Zimmerman said donors are approaching the 2020 race like the Kentucky Derby, betting on multiple candidates hoping that at least one in the crowded field of more than 20 people running will finish on top.

"The donor and political community don't place their bets based on the polls," he said. "Buttigieg's historic candidacy, message and great political skills explains why so many Obama and Clinton donors want to get to know him."

He added: "However, many are hedging their bets."

Possibly one of the biggest endorsements Buttigieg has received from Obama's world of donors came from Orin Kramer, a top fundraiser and donor to Obama in 2008 and 2012 and supporter of Clinton in 2016.

Buttigieg met with Kramer while he was in New York earlier this month, according to two sources with knowledge of the meeting. Kramer, a hedge fund manager who founded Boston Provident LP, donated $2,800 to the campaign, the max allowed in the primary.

But Kramer's support will certainly provide a powerful opening to longtime Democratic donors in New York. According to Open Secrets, Kramer and his wife donated more than $2.6 million between 1990 and 2016 to a range of politicians.

David Schulte, a Chicago investment banker, represents the kind of veteran Democratic Party donor who was skeptical of Buttigieg at first.

"When I first heard about Mayor Pete, I thought it was a bit of a joke for someone from a small Midwestern city to try to make the leap to the White House," Schulte told CNN.

Then, early one March morning, Schulte said he was shaving and watching MSNBC's Morning Joe when he heard an interview with Buttigieg.

"It suddenly occurred to me that I was listening to the voice of a man who was very smart, very measured and not a screamer about Trump or anything else," he said. "He was just a calm, intelligent voice who impressed the hell out of me."

Within days, Schulte had donated $2,800 to Buttigieg with the goal of keeping his campaign going. That doesn't mean he will back Buttigieg above all the other candidates in the crowded Democratic field, he said. But it bodes well for the mayor.

"It's early yet in the life of this presidential campaign," Schulte said. "But I like the idea of him, and I like the idea of doing what I can to boost his candidacy."