“I don’t feel like he’s been disloyal to me,” Mr. Christie said in a two-hour interview last week in which he stressed both his close relationship with the president and admitted to few regrets about his record in two terms as governor. “It’s been a long time he and I’ve been friends, and talking with each other, through a number of different jobs for me and a number of different situations and iterations for him.”

Sitting in an upholstered chair in a room at Drumthwacket, the governor’s mansion, Mr. Christie defended Mr. Trump as well as his own role in the transition, which he said went off the wheels after his departure and was the reason for “75 percent” of the president’s woes last year. To this day, Mr. Christie said he is unsure of what the president knew about his dismissal. (A new book about Mr. Trump by the author Michael Wolff suggests that it was at the request of Ivanka Trump).

As for his own thwarted presidential ambitions, he had a simple response to a question of whether he believes that without the Bridgegate scandal and Mr. Trump’s entry into the race, he could have been the Republican nominee in 2016 and living in the White House today.

“I do,” he said, then paused. “I don’t think there’s any other way to answer it.”

Asked about his low approval ratings in New Jersey, the crisis over the state’s infrastructure, and its budget struggles, Mr. Christie said there was little that he would do over.

“I feel like I’ve done the job as well or better than anybody who’s ever had it,” Mr. Christie said. “Would there be little things I would do differently? Sure. But over the sweep of the eight years, I think when I leave, people are going to see just how hard this stuff is. This is a tough state to govern.”