WASHINGTON — Rudolph W. Giuliani said on Monday that he provided President Trump with detailed information this year about how the United States ambassador to Ukraine was, in Mr. Giuliani’s view, impeding investigations that could benefit Mr. Trump, setting in motion the ambassador’s recall from her post.

In an interview, Mr. Giuliani, the president’s personal lawyer, described how he passed along to Mr. Trump “a couple of times” accounts about how the ambassador, Marie L. Yovanovitch, had frustrated efforts that could be politically helpful to Mr. Trump. They included investigations involving former Vice President Joseph R. Biden Jr. and Ukrainians who disseminated documents that damaged Mr. Trump’s 2016 campaign.

The president in turn connected Mr. Giuliani with Secretary of State Mike Pompeo, who asked for more information, Mr. Giuliani said. Within weeks, Ms. Yovanovitch was recalled as ambassador at the end of April and was told that Mr. Trump had lost trust in her.

The circumstances of Ms. Yovanovitch’s ouster after a smear campaign engineered in part by Mr. Giuliani were documented during testimony to the House Intelligence Committee, where she was a key witness in impeachment proceedings against Mr. Trump. Mr. Giuliani has made no secret of his role in flagging concerns about Ms. Yovanovitch to Mr. Trump.

But Mr. Giuliani’s account, in an interview with The New York Times on Monday evening, provided additional detail about the president’s knowledge of and involvement in one element of a pressure campaign against Ukraine.

Mr. Giuliani’s interview came as the House prepared for a vote on Wednesday to impeach Mr. Trump. The articles of impeachment put forward by Democrats accuse the president of abusing the power of his office to push Ukraine to help him politically and of obstructing Congress by blocking testimony from key officials. Over several weeks of testimony, Democrats assembled a case that Mr. Trump withheld military aid from Ukraine and denied its president an Oval Office meeting as he sought a commitment from the Ukrainians for the investigations promoted by Mr. Giuliani.

In conversations in the first months of the year with the president, Mr. Giuliani, by his account, cast Ms. Yovanovitch as impeding not only investigations in Ukraine that could benefit Mr. Trump, but also Mr. Giuliani’s efforts to gather evidence to defend him — and target his rivals — in the United States.

“There’s a lot of reasons to move her,” Mr. Giuliani said, asserting that his briefings of Mr. Trump and Mr. Pompeo most likely played a role in their decision to recall Ms. Yovanovitch.

“I think my information did,” he said. “I don’t know. You’d have to ask them. But they relied on it.”

He added that he did not recommend that Mr. Trump or Mr. Pompeo recall Ms. Yovanovitch. “I just gave them the facts,” he said. “I mean, did I think she should be recalled? I thought she should have been fired.” He said, “If I was attorney general, I would have kicked her out. I mean — secretary of state.”

Testimony in the impeachment proceedings as well as other information have shown that Mr. Giuliani’s claims about Ms. Yovanovitch were either unsubstantiated or were taken out of context. In the interview, he portrayed himself as personally involved in the effort to derail a career diplomat around the time he was considering business arrangements with some of the Ukrainians funneling information to him.

Mr. Giuliani told the president and Mr. Pompeo that Ms. Yovanovitch was blocking visas for Ukrainian prosecutors to come to the United States to present evidence to him — and also to federal authorities — that he claimed could be damaging to Mr. Biden and his son Hunter Biden, and to Ukrainians who distributed documents that led to the resignation of Mr. Trump’s 2016 campaign chairman, Paul Manafort.

Mr. Giuliani also claimed, based on his own interviews with those prosecutors, that Ms. Yovanovitch had sought to block investigations in Ukraine. And he relayed vague claims that she had been bad-mouthing the president.

“I think I had pointed out to the president a couple of times, I reported to the president, what I had learned about the visa denials,” Mr. Giuliani said, as well as the claims that she ordered one Ukrainian prosecutor to drop cases. “I may or may not have passed along the general gossip that the embassy was considered to be a kind of out-of-control politically partisan embassy, but that was, like, general gossip, I didn’t report that as fact.”

Mr. Giuliani had told The New Yorker in an article published on Monday that he needed Ms. Yovanovitch “out of the way,” and that she “was going to make the investigations difficult for everybody.”

Ms. Yovanovitch, a 33-year veteran of the Foreign Service, testified in the impeachment proceedings that Mr. Giuliani helped lead a smear campaign against her based on what she described as scurrilous lies, and she described the State Department as capitulating to the president’s demands to recall her.

There is no evidence that she had disparaged Mr. Trump, nor that she had issued a do-not-prosecute list, as one of Mr. Giuliani’s prosecutor sources once claimed.

But, by Mr. Giuliani’s account on Monday, the information he was spreading about her seemed to find a receptive audience at the highest reaches of the United States government and led Mr. Trump to involve Mr. Pompeo.

Mr. Giuliani told The Times that after he briefed Mr. Trump on the claims, the president said “either ‘discuss it with Mike’ or ‘turn it over to Mike.’” Mr. Giuliani said he could not recall “if he had me call him, or him call me — but he put us together so that Pompeo could evaluate it.”

Mr. Giuliani’s account of the phone calls with Mr. Pompeo seems to be corroborated by emails released by the State Department to a liberal watchdog group that had filed a public records lawsuit. The emails reflect at least two telephone calls between the men in late March, including one that was arranged with guidance from Mr. Trump’s personal assistant.

Mr. Giuliani said that Mr. Pompeo asked him whether he had anything in writing, so Mr. Giuliani sent a timeline listing events related to some of the claims about Ms. Yovanovitch, the Bidens’ work in Ukraine and other matters.

Mr. Pompeo subsequently requested more detailed information, Mr. Giuliani said, so he had someone hand deliver to Mr. Pompeo’s office an envelope containing a series of memos detailing claims made by a pair of Ukrainian prosecutors in interviews conducted by Mr. Giuliani and his associates in January. The existence of those memos has been previously reported, as has Mr. Giuliani’s hope that Mr. Pompeo would pass them along to State Department investigators and the F.B.I. as a way of prompting an investigation in the United States that could benefit Mr. Trump.

“What I thought was, a really smart guy and he’s going to see what else is involved,” Mr. Giuliani said, referring to Mr. Pompeo. “And then he’ll be the one referring it to the F.B.I. And maybe they’ll take it from him and also it won’t look like I’m pushing the F.B.I. to do it.”

One of the interviews detailed in a memo sent to Mr. Pompeo was conducted by phone with Viktor Shokin, a former Ukrainian prosecutor who was denied a visa by the State Department. He was denied the visa because he was seen as having wasted American assistance money that had been allocated to his office for anti-corruption programs, according to testimony in the impeachment inquiry.

Mr. Shokin “wanted to come to the United States to share information suggesting that there was corruption at the U.S. Embassy,” testified George P. Kent, a State Department official. “Knowing Mr. Shokin, I had full faith that it was bunch of hooey, and he was looking to basically engage in a con-game out of revenge because he’d lost his job.”

Another Ukrainian prosecutor, Yuriy Lutsenko, had traveled to New York to be interviewed by Mr. Giuliani for hours over two days in January, and information he relayed was included in memos sent to Mr. Pompeo.

Mr. Giuliani’s efforts in Ukraine have come under scrutiny from federal prosecutors examining whether he violated laws requiring Americans to publicly disclose when they lobby government officials or communicate with journalists on behalf of foreign political interests.

Yet Mr. Giuliani traveled to Europe this month, as first reported by The Times, to meet with some of those same Ukrainian prosecutors to continue gathering information to try to undercut the impeachment case, including through a series of programs on a conservative cable network.

Mr. Trump has said that Mr. Giuliani will submit a report of his findings to Attorney General William P. Barr and Congress.

Mr. Giuliani has shared some information gathered on the trip with Mr. Trump — but “not too much” — the president told reporters on Monday. He added that Mr. Giuliani “knows what he is doing.”

Mr. Giuliani would not comment on any conversations with Mr. Trump about the report from his most recent trip. He said he has not spoken with Mr. Barr about it. He has spoken to “several” members of Congress about his findings, he said, but he would not identify them, explaining, “It’s all very confidential.”

Christopher Cameron contributed reporting.