"We do not pay candidates to appear," Zucker told BuzzFeed editor Ben Smith in an interview at the Paley Center for Media on Thursday.
Variety reports CNN had previously declined to comment on Trump's demand that the network give $5 million to charity in exchange for his appearance on the debate stage.
At a rally in Georgia on Monday, Trump told supporters: "How about we do this for CNN: I won't do the debate unless they pay me $5 million, all of which money goes to the Wounded Warriors or goes to vets?" Trump accused the network of not treating him unfairly in its coverage of his meeting with black pastors on Monday.
Politico reports Trump pulled a similar move before September's GOP debate. He penned a letter to Zucker asking him to donate all profits from the televised event to veterans charities. CNN never issued an official response, and Trump ended up participating in the debate.