Former President Donald J. Trump sought to move his Manhattan criminal case into federal court on Thursday, filing the unusual request three months after he was convicted in state court.

The long-shot bid marks Mr. Trump’s latest effort to stave off his sentencing in state court in his hush-money trial, in which he was convicted of falsifying records to cover up a sex scandal.

He is scheduled to receive his punishment on Sept. 18, just seven weeks before Election Day, when he will square off against Vice President Kamala Harris for the presidency.

“The ongoing proceedings will continue to cause direct and irreparable harm to President Trump — the leading candidate in the 2024 presidential election — and voters located far beyond Manhattan,” Mr. Trump’s lawyers, Todd Blanche and Emil Bove, wrote in the filing.

Their filing came even as the Trump legal team is awaiting the result of a separate effort to postpone the sentencing; it opened a second front that could complicate the first.

On Aug. 15, Mr. Trump asked the state court judge who presided over the trial, Juan M. Merchan, to delay the sentencing until after Election Day. Mr. Trump’s lawyers argued that they needed more time to challenge his conviction on the basis of a recent Supreme Court ruling granting presidents broad immunity for official acts.