Mr. Gates was looking to re-establish himself as a Washington power broker after spending the better part of the decade before the 2016 campaign working with Mr. Manafort, his mentor and business partner, for Russia-aligned Ukrainian interests that paid them tens of millions of dollars.

Mr. Broidy, who had pleaded guilty in 2009 in a pension fund fraud case, was looking for help courting foreign government clients for a defense contractor he had purchased in 2015, and pushing for policies that favored clients and prospective clients.

Although Mr. Gates’s role on Mr. Trump’s presidential campaign had shrunk dramatically after Mr. Manafort resigned under pressure as its chairman months before the election, he maintained connections to numerous Trump advisers, including two key players in Mr. Trump’s orbit with whom he had worked planning the presidential inauguration — Mr. Broidy, who was a vice chairman of the inaugural committee’s finance team, and the billionaire California investor Thomas J. Barrack Jr., who served as chairman of the inaugural committee.

After the inauguration, Mr. Gates began receiving monthly consulting payments for help navigating the new administration from a company headed by Mr. Barrack, Colony NorthStar, which paid Mr. Gates $20,000 a month, and one owned by Mr. Broidy, which paid Mr. Gates $25,000 a month, according to documents and people familiar with the relationships, who requested anonymity to discuss private business arrangements.

The payments came despite the fact that Mr. Gates and Mr. Manafort were emerging as subjects of federal and congressional investigations looking into their lucrative Ukraine work, and any connections between the Trump campaign and Russia.

Other Washington consultants were puzzled by the willingness of clients to hire Mr. Gates or Mr. Manafort at a time when it seemed that the looming investigations would limit their effectiveness and access to Mr. Trump’s advisers, some of whom had tried to bar Mr. Gates from working with the administration. Mr. Gates maintained at least some access, in part because he was seen as having the blessing of Mr. Barrack, a close friend and business associate of Mr. Trump’s, according to a Trump associate.

But when Mr. Gates was indicted in October, Mr. Trump’s allies began to further distance themselves. Colony NorthStar quickly terminated its arrangement with Mr. Gates, according to someone familiar with it.