Facing a possible ban in the United States, TikTok has scrambled to deploy perhaps its most powerful weapon: its creators.

The hugely popular video service began recruiting dozens of creators at the end of last week, asking them to travel to Washington to fight a bill being debated in Congress. Under the proposal, TikTok’s Chinese owner, ByteDance, would need to sell the app or it would be blocked in the United States.

Many of the creators have met with lawmakers and posted videos about their opposition to the bill with the hashtag #KeepTikTok, often with the irreverent humor the app is known for.

“So old white people boomers we call Congress-people are trying to ban TikTok, and I’m not having it,” Giovanna González, a TikTok creator better known as @TheFirstGenMentor, posted in a video on Tuesday, with the U.S. Capitol visible in the distance behind her.

So far, the efforts have not panned out. The House passed the bill Wednesday with broad bipartisan support. But it may face an uphill battle in the Senate, where TikTok creators are already setting their sights.

Unlike traditional lobbyists, the creators were not paid to support TikTok. However, the company covered their transportation, lodging and meals, including a festive dinner at the Bazaar by José Andrés, a restaurant in the Waldorf Astoria hotel.

The creators said they were speaking for themselves, and posted personal and often emotional videos about what the app meant to them. The arrangement was similar last year when TikTok brought creators to Washington to defend the app as Shou Chew, TikTok’s chief executive, testified before Congress.

President Biden and congressional lawmakers have increasingly voiced concern that TikTok’s Chinese ownership poses grave national security risks to the United States, including the ability to meddle in elections. The bill, which is supported by Mr. Biden, is meant to force ByteDance to sell TikTok to non-Chinese owners within six months. The president could sign off on the deal if it resolved national security concerns. Otherwise, the app would be banned.

TikTok has said repeatedly that Beijing officials have no say in how the app operates, nor does the Chinese government have access to American user data, which is stored in the United States. The company said after the vote that it was “hopeful that the Senate will consider the facts, listen to their constituents and realize the impact on the economy” and TikTok’s 170 million U.S. users.

Several creators said they told lawmakers and their aides about how the app had influenced their lives and promoted their businesses, as they urged “no” votes. Many posted videos with Representative Ro Khanna, Democrat of California, who opposed the bill. One creator, a child safety advocate named Dani Morin, said that she met with Senator Laphonza Butler and Representative Pete Aguilar, both Democrats of California.

Paul Tran, who runs a skin care brand with his wife, Lynda Truong, called Love & Pebble, said he didn’t even know about the bill when TikTok approached him for the trip last week. “I said, ‘For sure I’m going out there,’” he said, adding that 90 percent of his company’s sales come from the app. “Most people still think that TikTok is just some fun app, but really, businesses are being made here.”

TikTok helped coordinate television appearances — Mr. Tran said he joined “Good Morning America” this week — and protests outside the Capitol and the White House, where creators held signs with messages like “TikTok changed my life for the better.”

Creators appeared at a news conference with lawmakers who opposed the bill, like Representative Maxwell Frost, Democrat of Florida. A lawyer for the American Civil Liberties Union also spoke with the creators at their hotel about potential constitutional problems with the bill, the organization said.

“We’re proud that so many creators and community members would be willing to take time away from their families, work and businesses, on such short notice, to advocate against a rushed bill that would trample Americans’ constitutional rights of free expression,” Alex Haurek, a spokesman for TikTok, said in a statement. He said that more than 100 creators and members of the TikTok community joined the push.

Last week, TikTok sent a pop-up message to many of its users urging them to call their legislators. Several congressional offices said they were flooded with calls that day.

Many creators flew to Washington on Monday and planned to leave Wednesday.

On Wednesday, many creators posted videos expressing disappointment with the House vote but optimism about the bill’s chances in the Senate.

“Please do not lose hope, please do not get too upset — there are a lot of things we can do before this app is gone,” an activist and feminist who posts under @FamousBlonde told her followers. Her caption included a note for Representative Jeff Jackson, Democrat of North Carolina, to “kick rocks.”

Mr. Jackson is the most popular member of Congress on TikTok with 2.5 million followers. He voted in favor of the bill, spurring more than 18,000 comments on one of his videos on Wednesday.

Tiffany Yu, a 35-year-old disability advocate in Los Angeles who was among the creators in Washington this week, said that when she posted videos about the bill, she realized that many users were still in the dark about the machinations in Congress.

“One of the comments was like, I had no idea this was happening,” she said. “There’s still a gap between what’s happening on the Hill and the people we’re able to reach.”