WASHINGTON — Former Speaker John Boehner, Republican of Ohio, says in a new memoir that he regrets supporting the impeachment of President Bill Clinton, calling it a partisan attack that he now wishes he had repudiated.

In his book “On the House: A Washington Memoir,” a copy of which was obtained by The New York Times, Mr. Boehner blames Representative Tom DeLay of Texas, then the No. 2 Republican, for leading a politically motivated campaign against Mr. Clinton over his affair with Monica Lewinsky, a White House intern.

The Republican-led House voted to impeach Mr. Clinton on two counts in 1998. He was acquitted by the Senate.

“In my view, Republicans impeached him for one reason and one reason only — because it was strenuously recommended to us by one Tom DeLay,” Mr. Boehner writes. “Tom believed that impeaching Clinton would win us all these House seats, would be a big win politically, and he convinced enough of the membership and the G.O.P. base that this was true.

“I was on board at the time,” Mr. Boehner went on. “I won’t pretend otherwise. But I regret it now. I regret that I didn’t fight against it.”

Mr. Boehner’s memoir, whose cover is a photograph of the former speaker holding a glass of merlot, with a lit cigarette in an ashtray beside him — his natural habitat for decades — is full of colorful stories from his time in Congress.

He pulls no punches for those he views as far-right bomb-throwers in his party. (He saves several particularly forceful insults for Senator Ted Cruz of Texas.) And he issues a stinging denunciation of Donald J. Trump, saying that the now former president “incited that bloody insurrection” by his supporters at the Capitol on Jan. 6 and that the Republican Party has been taken over by “whack jobs.”

Mr. Trump’s “refusal to accept the result of the election not only cost Republicans the Senate but led to mob violence,” Mr. Boehner writes.

Mr. Boehner also details on the record some of Capitol Hill’s most talked-about exchanges, including the time that Representative Don Young, Republican of Alaska, pulled a knife on Mr. Boehner on the House floor after a critical speech about sweetheart projects going to Alaska.

“Sometimes I can still feel that thing against my throat,” Mr. Boehner writes. (The two would later patch things up, and Mr. Boehner would serve as the best man in Mr. Young’s wedding.)

Mr. Boehner also relays an encounter in his office in which Mark Meadows, then a Republican representative from North Carolina and a leader of the right-wing Freedom Caucus, dropped to his knees to beg for forgiveness after a political coup attempt against Mr. Boehner failed.

“Not long after the vote — a vote that like many of the Freedom Caucus’s efforts ended in abject failure — I was told that Meadows wanted to meet with me one-on-one,” Mr. Boehner recalled. “Before I knew it, he had dropped off the couch and was on his knees. Right there on my rug. That was a first. His hands came together in front of him as if he were about to pray. ‘Mr. Speaker, please forgive me,’ he said, or words to that effect.”

Mr. Boehner says he wondered, in the moment, what Mr. Meadows’s “elite and uncompromising band of Freedom Caucus warriors would have made of their star organizer on the verge of tears, but that wasn’t my problem.”

Mr. Boehner looks down at the man who would later become Mr. Trump’s White House chief of staff.

“I took a long, slow drag of my Camel cigarette,” he writes. “Let the tension hang there a little, you know? I looked at my pack of Camels on the desk next to me, then I looked down at him, and asked (as if I didn’t know): ‘For what?’”

Maggie Haberman contributed reporting from New York.