Donald J. Trump has joined TikTok, the social media app that he tried to ban during his presidency but that he more recently has embraced as he and his campaign try to reach younger voters before November’s general election.
Mr. Trump’s account shared its first video on Saturday night, when he attended an Ultimate Fighting Championship bout in New Jersey. In the post, Mr. Trump stands in the bowels of an arena next to Dana White, the U.F.C. chief executive. “The president is now on TikTok,” Mr. White says.
“It’s an honor,” Mr. Trump responds, a striking change of tune from his efforts to ban the app through an executive order over national security concerns.
Then, the video, just 13 seconds long, cuts to clips of Mr. Trump walking into the packed arena and receiving a raucous and warm reception from U.F.C. fans while Kid Rock’s song “American Bad Ass” plays in the background.
Mr. Trump’s inaugural post is largely an extension of his campaign’s efforts on social media to amplify the hero’s welcome he often gets at U.F.C. fights, where the largely young and male audience tends to overlap with his base.
But his decision to join TikTok was a striking turnabout in his views of the social video app, which has roughly 170 million American users and an audience that skews younger than those of other social media platforms.
While he was president, Mr. Trump expressed national security concerns about the app’s owner, the Chinese company ByteDance. In 2020, he issued an executive order requiring the company to divest from its American assets. That order was blocked in federal court before Mr. Trump left the White House.
This year, Congress passed, with broad bipartisan support, a bill to force TikTok’s owner to sell the app or have it banned in the United States. Mr. Trump said he opposed such a ban, explaining his shift by saying that he did not want to alienate young people or risk making Meta, the owner of Facebook, Instagram and WhatsApp, more dominant.
And after President Biden signed the bill, Mr. Trump made a direct plea to young voters. “Young people, remember: Crooked Joe Biden is the one that wants to take your TikTok away from you,” he said on his social media site Truth Social.
Steven Cheung, a spokesman for the Trump campaign, framed Mr. Trump’s joining TikTok as part of the campaign’s efforts to connect with younger voters. “We will leave no front undefended and this represents the continued outreach to a younger audience consuming pro-Trump and anti-Biden content,” he said in a statement.
Mr. Biden’s campaign joined the app in February as part of its efforts to help improve the president’s flagging support among young voters. Its videos are largely a steady stream of anti-Trump content. So far, its account has 335,600 followers, while Mr. Trump’s has 1.4 million.
An internal analysis within TikTok found nearly twice as many pro-Trump posts as pro-Biden ones on the platform since November: There were 1.29 million pro-Trump posts to 651,000 pro-Biden posts.
Lawmakers and intelligence officials remain concerned that the app may be a threat to national security, partly because of how the Chinese government could use it to spread propaganda, particularly in an election year.
The company said last month that it would introduce new measures to limit the spread of videos from state-affiliated media accounts, including from Chinese and Russian outlets. TikTok has filed a lawsuit against the federal government contesting the law to force a sale or a ban.
