"This is a president of the United States running wild, running amok, it's constant, it's everything," Lemon said. "All of it together raises serious questions about his fitness for office... The volume of what this president has said and tweeted-- just in the past 24 hours-- puts us in danger of being overwhelmed, in danger of forgetting just how wrong, how bad for the country a lot of this is."
Lemon, who recently moderated a presidential debate, slammed the president for his "outrageous" retweet that referred to himself as the "King of Israel" and the "second coming of God" as well as his doubling down of his criticism of American Jews who are "disloyal" if they vote Democrat.
He mocked Trump for how he enunciated the word "absurd" when he blasted Danish Prime Minister Mette Frederiksen for what he described as a "nasty" response to his interest in buying Greenland from Denmark.
The "CNN Tonight" host then blasted the president for joking to a group of military veterans that he wanted to give himself the Medal of Honor.
"That clearly was a joke... but let's remember that the Medal of Honor is the United States' highest military decoration. It's awarded to a member of the armed forces for gallantry and bravery and combat beyond the call of duty... nothing for this president, who never served in the military to joke about," Lemon scorned the president.
"This is not normal and it's gotta make you wonder about this president's fitness for office."
Lemon went on to question Trump's fitness for office to CNN commentator and former 2016 candidate Gov. John Kasich.
"Does it seem like he's behaving more erratically than usual?" Lemon asked. "Is he fit for office? And if he isn't what should happen?"
Kasich didn't directly answer the questions but responded by boasting his lack of support for Trump during the 2016 election and warned Democrats to pick a 2020 candidate "who can win."