Mr. Bolton’s relationships with most of the associates date back decades, to his days working in positions related to foreign policy in the Reagan administration. But he continued working with them in the dozen years since he has been out of government, serving as an adviser to Mr. Wurmser’s company, according to its website, while relying on Mr. Kupperman, Ms. Tinsley and several other associates to help run a constellation of conservative political organizations that he founded to advance his foreign policy views and political prospects.

The activity brought Mr. Bolton into regular contact with some of the biggest donors on the right, while giving him a platform to explore his own possible presidential campaign in 2016 and to be an advocate for confrontational strategies in dealing with Iran, North Korea and Russia.

Mr. Bolton’s continued reliance on longtime associates in either informal or temporary capacities at the National Security Council has raised concerns among government watchdog organizations and agency veterans and scholars. They say it creates questions of conflicts of interest and an echo chamber of identical views with little room for dissent at the agency charged with coordinating policy throughout the government’s military, foreign policy and intelligence communities and synthesizing the best advice for the president.

“Very much like the president, Bolton has picked a small coterie of people from past lives who look more like cronies and buddies than they do the array of senior experts on different issues that past national security advisers have brought in,” said David J. Rothkopf, a former Clinton administration official who wrote a definitive history of the National Security Council.

Rather than fulfilling Mr. Trump’s promise that he would fill his administration with “the best people,” Mr. Rothkopf said, the president has got “this highly controversial national security adviser who has never crossed a bridge he hasn’t burned behind him, who is surrounding himself with what appears to be a second-tier group of advisers who have spent a disproportionate amount of time on the swamp side of things — as consultants or working on his extreme political projects.”