SEOUL—North Korea named a veteran diplomat with extensive U.S. experience as its chief negotiator for working-level talks with Washington, while praising President Trump for dismissing national security adviserJohn Bolton.

Kim Myong Gil, recently the North’s ambassador to Vietnam, took part in nuclear negotiations with the U.S. in 2000. Close Pyongyang watchers had suspected he would be tapped for the coming talks after he was photographed with leader Kim Jong Un at June 30’s impromptu meeting with Mr. Trump at Korea’s demilitarized zone.

In a Friday state-media report, Kim Myong Gil referred to himself as the chief delegate in nuclear talks and called the removal of “nasty troublemaker” Mr. Bolton wise. He cited Mr. Trump’s criticism Wednesday of Mr. Bolton’s maximalist strategy, seeking disarmament before sanctions relief, and the president’s suggestion that a new method could end months of negotiating gridlock.

“The political decision to turn to a new alternative, finding it utterly impossible to make it with old method is the manifestation of the political perception and disposition peculiar to President Trump,” Mr. Kim said.

Mr. Kim’s formal designation as a chief negotiator is a sign that Pyongyang remains committed to restarting denuclearization talks, as agreed to by Messrs. Trump and Kim at their June 30 meeting. Within weeks of that meeting, though, the North took offense at Trump administration comments and returned to provocations like firing short-range missiles and issuing angry state-media missives.