In the run-up to the regulatory settlement, Digital World ousted its original chief executive and main promoter, Patrick Orlando, and revamped its board. Mr. Orlando, however, remains a large Digital World shareholder.

Digital World had lobbied hard to get shareholders — most of whom are retail investors — to approve the measure to give the company more time to complete the merger. It hired an advisory firm to encourage 65 percent of the company’s shareholders to vote for the extension.

Trump Media also lent support to the get out the vote, sending email alerts to Truth Social subscribers urging them to vote for the extension if they were also Digital World shareholders.

“Thank you for all of the outstanding support. Please understand my silence. We remain focused on the task at hand and are watching every word we say,” Eric Swider, Digital World’s chief executive, said on Truth Social shortly after the result of the vote on an extension was announced.

The merger still faces hurdles.

In early August, Trump Media recommitted itself to completing the deal only after it received new terms that would strengthen Mr. Trump’s control over the merged company. The revised agreement with Trump Media anticipates the merger closing by the end of December. Mr. Trump’s company also can terminate the agreement before then, if Digital World cannot meet an Oct. 9 deadline for submitting amended regulatory filings.

If the deal is completed, Mr. Trump will be the newly merged company’s largest shareholder.

Shares of Digital World jumped after the company announced the result of the vote. With a market valuation of well over $600 million, post-merger Trump Media would be one of Mr. Trump’s most valuable holdings.