Mr. Avenatti is accused of impersonating and defrauding Stormy Daniels when he served as her lawyer. The decision means he will likely cross-examine her during his trial.
Michael Avenatti, the brash lawyer who became one of former President Donald J. Trump’s most outspoken foils before being felled by accusations of fraud, will represent himself for the remainder of his criminal trial in Manhattan, a judge ruled on Tuesday.
Mr. Avenatti made the request just after a lunch break but before jurors had returned to a courtroom in Federal District Court in Manhattan, where testimony in his trial on wire fraud and aggravated identity theft began on Monday.
He is accused of impersonating his client — the pornographic film actress Stormy Daniels — and convincing her literary agent to send him nearly $300,000 in publisher’s payments meant for her.
On Tuesday morning the third witness in the trial, Judy Regnier, a former office manager for Mr. Avenatti’s firm in 2018, testified that the firm had been short on money at the time.
But before her cross-examination began, Mr. Avenatti told Judge Jesse M. Furman that he and his lawyers disagreed on how they would question Ms. Regnier.
“I’m making a formal application to represent myself,” he said, adding that there had been a “breakdown” between him and his existing defense lawyers.
After questioning Mr. Avenatti about his decision and explaining its risks, Judge Furman agreed to allow him to serve as his own lawyer.
The judge noted that Mr. Avenatti had little experience with criminal cases, and cautioned him to “make your choice with your eyes wide open.”
The decision makes it likely that Mr. Avenatti will cross-examine Ms. Daniels, who is widely expected to be called as a defense witness during the trial.
That spectacle would cap a contentious split between what was once hailed by some as a courageous, if unlikely, pair challenging a sitting president.
In a 2018 lawsuit filed by Mr. Avenatti, Ms. Daniels, whose legal name is Stephanie Clifford, said she had a sexual relationship with Mr. Trump more than a decade earlier. Before the 2016 election, she said, she received a $130,000 payment from the president’s former lawyer, Michael D. Cohen, to keep quiet about the relationship.
But Mr. Avenatti soon ran afoul of the law. He was indicted and later convicted on charges that he tried to defraud Nike for millions of dollars, and was charged separately in the case involving Ms. Daniels.