Last summer, after Christine Blasey Ford said that Judge Kavanaugh had sexually assaulted her when they were in high school, Mr. Avenatti came forward with another accuser, Julie Swetnick. With little detail, Ms. Swetnick escalated the allegations, describing parties attended by the judge’s circle of friends, where she said girls had been gang-raped.

On the eve of Dr. Blasey and Judge Kavanaugh’s testimony to Congress, some felt the claims brought by Mr. Avenatti’s client were gasoline on a fire, intensifying the political frenzy around what was widely considered a test for the #MeToo movement. Noting inconsistencies in Ms. Swetnick’s account, the chairman of the Senate Judiciary Committee questioned whether Mr. Avenatti had deliberately misled Congress and referred him and his client for criminal investigation.

In his push against the judge, Mr. Avenatti said he had witnesses who could corroborate his client’s claims, but he never brought any forward publicly. (Last week, he said he still believed his client, and he reiterated that he had called for an F.B.I. inquiry to interview witnesses.) And at the peak of the Stormy Daniels case, he said he had more women alleging hush money payments tied to Mr. Trump, but he produced none.

Mr. Avenatti denied that he had chased the cases for attention.

“I haven’t repositioned myself to remain in the spotlight,” he said, claiming he had received 50 to 200 unsolicited requests for representation daily over the last year. “In many instances, the cases that I’ve gotten involved in have changed the spotlight.”

Though he never held political office, when Mr. Avenatti hinted at a run for president, he was taken somewhat seriously. “We must be a party that fights fire with fire,” Mr. Avenatti said at a Democratic fund-raiser in Iowa in August, sounding like a candidate. “When they go low, I say hit back harder.”

He bristled at the idea that he had emerged out of nowhere.

“I don’t feel like I get enough credit for my track record of success relating to cases,” Mr. Avenatti said, raising his voice with exasperation. “People act like I was a nobody before Stormy Daniels, and it’s ridiculous.”

As a plaintiff’s lawyer, Mr. Avenatti had won some big settlements. He sued KPMG for audit malpractice, and the company settled for $22 million. He won $80 million from a cemetery accused of overstuffing its plots, and half a billion from the makers of defective surgical gowns. Two of his cases before Ms. Daniels had landed him on “60 Minutes,” he pointed out.