In fact, Mr. Conway withdrew his name from consideration for a top job at the Justice Department, running its civil division, before he ever started. And he has known Mr. Trump for decades, since he lived in Manhattan at Trump World Tower and declined to sit on the condo board, a spot that his wife took in his stead.

In more recent history, Mr. Conway spent time with Mr. Trump on election night and at the wedding of the Treasury secretary, Steven Mnuchin, in June 2017, when Mr. Trump even commended him on turning down the job because it would have meant reporting to a “weak” leader, former Attorney General Jeff Sessions.

Since Mr. Conway has become more vocal in his criticism of the president, Mr. Trump has referred to him repeatedly as “Mr. Kellyanne Conway” and claimed that in his diatribes against the president, he is simply trying to gain attention through the reflected glory of his wife. On Wednesday, Mr. Trump wrote on Twitter that Mr. Conway, “often referred to as Mr. Kellyanne Conway by those who know him, is VERY jealous of his wife’s success & angry that I, with her help, didn’t give him the job he so desperately wanted.”

In an interview, Mr. Conway dismissed the idea that he was coasting off interest in his wife, and said that in the course of a long marriage, it is hard to separate who is responsible for whose fortune and fame.

“The way we structured our lives before the campaign, it enabled her to build her business so she could become the campaign manager,” said Mr. Conway, who was previously a partner at the law firm Wachtell Lipton Rosen & Katz. “I helped in ways that enabled her to go off and be the campaign manager, and go off to the White House in the spring of 2017.”

When the couple relocated its family to Washington from New Jersey, Mr. Conway gave up his partner status at the law firm, which does not have an office in the District of Columbia, and became “of counsel.”

Mr. Conway said his motivation to publicly attack the president had been driven, at least in part, by feeling responsible for having played a small role in electing him, even if it was a tangential one of supportive spouse to the campaign manager.