The US president, 72, and the Prince of Wales, 70, met for tea at Clarence House on Monday afternoon and Mr Trump revealed the subject of global warming came up.
The pair have conflicting views on the issue - Charles is a strong advocate for the environment, while Mr Trump announced the US would withdraw from the Paris Agreement on climate change mitigation in 2017.
The former businessman said his meeting with Prince Charles was meant to last 15 minutes and went on for an hour and a half, during which the royal did “most of the talking”.
Mr Trump said: "He is really into climate change and I think that’s great. I want that, I like that.”
“What he really wants and what he feels warmly about is the future. He wants the best climate for the future. He wants a good climate and not a disaster."
Does the US President believe in climate change?— Good Morning Britain (@GMB) June 5, 2019
Trump says he discussed climate change with Prince Charles, who he believes is 'a very good person' who 'wants to have a world that's good for future generations'. pic.twitter.com/QNlXhiS1mO
When pressed by Morgan about whether the US should take more responsibility, he said: "I did mention a number of things, I did say the United States right now has among the cleanest climates."
He then mentioned that China, India and Russia have “not very good air and not very good water.”
Asked if Charles moved him on the issue, Mr Trump said: "What moved me was his passion for future generations, he's really not doing this for him, he's doing this for future generations.
"This is real, he believes that. He wants to have a world that's good for future generations and I do, too.
"He's Prince Charles, he doesn't have to worry about future generations unless he's a very good person who cares about people, and that's what impressed me, maybe the most."
On Monday evening, the Queen hosted a state banquet for the president and first lady at Buckingham Palace.
The Prince of Wales and Duchess of Cornwall then attended a return dinner, on behalf of Her Majesty, at the US Ambassador’s London residence Winfield House on Tuesday night.
On the final day of the state visit, Mr Trump is joining the Queen, Prince Charles and prime minister Theresa May at the D-Day National Commemorative Event, at Southsea Common, Portsmouth.