Howard Gold, who lives down the street from Clooney in Los Angeles' tony Studio City neighborhood, hosted the group of Sanders supporters for a $27-a-person fundraiser. As part of that event, Gold and other organizers handed out $1 bills for attendees to throw at Clinton as she drove by.
Gold and others said the protest was meant to be a fun way to show what they called the absurdity around campaign finance laws. Gold said he doesn't support the former first lady because of her foreign policy views.
"She is the most militaristic of any of the candidates," Gold, 56, said, citing her tenure of secretary of state. "I really think she is."
Gold, whose family founded the 99 Cents Only Stores chain, withdrew the money from a bank, organizers said.
The Sanders supporters blasted "Hail to the Chief" and "We're in the Money" as Clinton drove by, and once she passed, the group danced in the street, stomping on the dollar bills.
Clinton was in Los Angeles for a rally earlier in the day and two fundraisers, including the evening event hosted by Clooney, the famed actor, and his wife, Amal Clooney, a renowned human rights attorney.
The Hillary Clinton fundraiser hosted by the Clooneys was a star-studded affair, according to sources inside the event.
In addition to the hosts, it was co-hosted by Marilyn and Jeffrey Katzenberg, the CEO of DreamWorks, Kate Capshaw and Steven Spielberg, the well-known director, and Cheryl and Haim Saban, the longtime Clinton donor and owner of Univision.
Celebrities in attendance included Jane Fonda, Ellen DeGeneres, Portia de Rossi, Jim Parsons and James Cameron, according to sources inside the event.
The is the second fundraiser the Clooneys have headlined with Clinton in as many days. The first was Friday night in San Francisco.
Both of the Clinton-Clooney fundraisers benefit the Hillary Victory Fund, a joint fundraising effort for the Clinton campaign, the Democratic National Committee and a host of state Democratic parties.
To co-host the event, a couple was asked to donate $353,400 to the fund. Single tickets cost $33,400.
Clinton's campaign defended the fundraisers on Friday by knocking Sanders for not raising money for Democrats, something Sanders has just recently started doing, not near the level Clinton has.
"Hillary Clinton has made it a priority to raise money for Democrats up and down the ballot and we're grateful to everyone who supports the party," said Christina Reynolds, a Clinton campaign spokeswoman. "We frequently hear about how much money Senator Sanders is raising, maybe he can send a few of those $27 donations to the DNC and state parties across the country to help the party he hopes to lead."
Clinton's event in San Francisco on Friday was protested by a group of roughly 100 people
chanting "Hey hey, ho ho, Hillary Clinton has got to go." The sentiment among that group was markedly anti-Clinton, with many in the group vowing to never vote for her.
The feeling at the Los Angeles fundraiser was different. Many of the protesters blew bubbles as fundraiser attendees drove by. And while some carried signs charging Clinton with being in the pocket of her wealthy contributors, many confided that, should she be the nominee, they would vote for her in November.
While Sanders' campaign did not organize the counter-fundraiser, it did use the Clooney events to do fundraising of its own.
The campaign ran an ad on Friday titled "27" that goes after her for the big-dollar fundraiser. The number refers to the average dollar donation to Sanders' campaign, something he regularly touts on the campaign trail. The ad ran in both San Francisco and Los Angeles.
"If you can't afford to attend tonight's event with Secretary Clinton," Jeff Weaver, Sanders' campaign manager, said of the ad, "we invite you to join Bernie's fundraiser for the low price of turning on your television."