The former N.B.A. star Dennis Rodman has always had an ability to grab the spotlight. There was the time he donned a wedding dress and claimed to marry himself. There were his stints on reality television and as a pro wrestler. And there was his unusual relationship with the North Korean leader, Kim Jong-un, to whom he sang “Happy Birthday” in 2014.
So when President Trump and Mr. Kim began their historic meeting in Singapore on Tuesday, it seemed inevitable that The Worm, as Mr. Rodman is known, would make an appearance.
The retired basketball star has met both men and forged unlikely ties to North Korea, traveling to the isolated authoritarian state several times and once taking a team of retired basketball players to Pyongyang, the North’s capital, to play before Mr. Kim.
In an emotional interview with CNN shortly after Mr. Trump and Mr. Kim shook hands, Mr. Rodman expressed his hopes for the meeting, declaring, “Today is a great day.”
Speaking to CNN from Singapore, Mr. Rodman wore sunglasses, a red “Make America Great Again” hat and a T-shirt bearing the name of PotCoin, a marijuana industry cryptocurrency that sponsored his trip. He teared up at times during the interview with Chris Cuomo as he recounted the criticism he received for visiting North Korea after Mr. Kim became leader.
Mr. Rodman said he got “so many death threats” after returning home.
“But I kept my head up high, brother,” he said. “I knew things were going to change. I knew it. I was the only one.”
“Today is a great day for everybody: Singapore, Tokyo, China, everything,” Mr. Rodman continued. “It’s a great day, and I’m here to see it. I’m so happy!”
While some people have criticized Mr. Rodman as an attention-hungry interloper, others have suggested he has a unique role in the warming ties between the United States and North Korea.
Mr. Cuomo said on CNN that Mr. Rodman “is our best resource at this point right now for understanding the minds of the two men, especially Kim Jong-un.”
His guest James R. Clapper Jr., the former director of national intelligence, said that “as weird as it is,” he agreed.
“This whole thing is unconventional,” Mr. Clapper said.
As in previous interviews, Mr. Rodman declined to directly answer questions about human rights abuses in North Korea. He acknowledged, however, that he was “very naïve” in 2013 when he first traveled there.
Mr. Rodman won two N.B.A. championships with the Detroit Pistons and three with the Chicago Bulls, and was known as much for his tough defense and rebounding as his hair dye and fingernail polish.
His N.B.A. fame helped him forge a connection with Mr. Kim, and he is one of the few people to have a relationship with both Mr. Kim and Mr. Trump. He appeared on “The Celebrity Apprentice,” the television show hosted by Mr. Trump, in 2009 and 2013. Mr. Trump praised Mr. Rodman’s first visit to North Korea, saying in 2013, “Maybe Dennis is a lot better than what we have.”
But he later lashed out at him. “Dennis Rodman was either drunk or on drugs (delusional) when he said I wanted to go to North Korea with him,” Mr. Trump tweeted in 2014. “Glad I fired him on Apprentice!”
Mr. Rodman said that Mr. Kim had asked him to pass along a message to Barack Obama, then president, but “Obama didn’t give me the time of day.”
Despite the earlier criticism from Mr. Trump, Mr. Rodman said that the president had acknowledged his contribution to ties with North Korea ahead of the Singapore meeting. A secretary for the president had called, Mr. Rodman said. “She said, ‘Dennis, Donald Trump is so proud of you. He thanks you a lot.’”
“And that means a lot,” he added. “After all these years, the fact that I somewhat had something to do with this North Korea situation, but I don’t want to take any credit, where credit is due. I think we all need to take credit.”
While Mr. Rodman said nothing about the many obstacles to a lasting peace between the two sides, he said contact between the leaders was an important start.
“Let’s just hope for the best,” Mr. Rodman said. “We don’t need a miracle, we just need the doors to be open so we can start afresh and make this world a better place.”