The actor admitted that he was shocked by the negative reaction to his alter ego, who he described as being opportunistic rather than "evil".
"I knew he was going to turn into a kind of a slimy villain, so I was looking forward to seeing how everybody reacted," he told TV Line.
"But I didn't know that people would get this into it... It's not that he's evil; he is just really invested in the product. He kind of considers it his show, so he wants it to do well."
On whether Ellis will change when Smash returns, he continued: "I think every show needs a villain, because without conflict there's nothing to watch on a one-hour drama.
"Nothing's set in stone, but I've gotten a pretty generous rundown of what's happening with my character in season two, and you can definitely look out for him a lot, doing some more [sneaky things]. I'm probably going to be even more hated."
Cepero also dismissed suggestions that Ellis should be killed off to appease viewers, saying: "He's a little too smart to be hit by a cab."
Smash airs Mondays at 10/9c on NBC.
> 'Smash': 'The Movie Star' recap
> 'Smash' soundtrack release date revealed