The latest attacks, directed at prominent black people, appeared to widen the racial divide that Mr. James spoke about on CNN.

“I would like to know why he considers these two successful black men ‘dumb,’” Torrey Smith, a wide receiver for the Carolina Panthers, said on Twitter. “I know why.”

Mr. Trump made his comment a day before a scheduled appearance on Saturday night in Ohio — home of the Cleveland Cavaliers and many LeBron James fans — to campaign for Troy Balderson, a state senator who is running in a special election for the House of Representatives.

Mr. Lemon came to Mr. James’s defense on Saturday morning, tweeting: “Who’s the real dummy? A man who puts kids in classrooms or one who puts kids in cages?” He added the hashtag #BeBest, a reference to an initiative by the first lady, Melania Trump, that aims to help children.

Stephanie Grisham, Ms. Trump’s communications director, said in a statement: “It looks like LeBron James is working to do good things on behalf of our next generation and just as she always has, the first lady encourages everyone to have an open dialogue about issues facing children today.”

Ms. Grisham added that Ms. Trump would be open to visiting Mr. James’s new school in Akron.

During the CNN interview, Mr. James said conversations about race had “taken over” in part because “our president is kind of trying to divide us.” “Kind of?” Mr. Lemon said, followed by a chuckle.

“He is,” Mr. James said. “He’s dividing us.”

Mr. James said his involvement in sports was the first time “I ever was around someone white,” adding, “And I got an opportunity to see them and learn about them and they got an opportunity to learn about me, and we became very good friends.”