"I feel increasingly comfortable and confident that we got it in the right balance," said Zucker, who is marking his sixth month at the helm of the cable news network and its affiliates.
CNN's priorities in giving extensive coverage to the trial of the Florida neighborhood watch volunteer on trial for murder were questioned last week during the height of political unrest in Egypt, a story that CNN International was spending virtually all of its time on. CNN's coverage continued Friday with the Zimmerman defense team's closing arguments.
Sid Bedingfield, a former CNN executive who now teaches journalism at the University of South Carolina, wrote online that he worries that CNN's Zimmerman coverage may mark a turning point in a move toward tabloid TV. News organizations should tread carefully in cases with potentially explosive racial overtones, he wrote.
A prominent press critic, Jay Rosen of New York University, suggested that a drive for ratings has trumped common sense. CNN has minted an instant hit with its nightly prime-time wrap-up of the Zimmerman case that Anderson Cooper hosts.
"What do they stand for?" Rosen wrote on his blog. "The same thing 'Entertainment Tonight' stands for. Television that occupies your attention, not for a purpose but merely for a while.
Zucker, appearing Friday at the IESE Business School, said that it's possible to cover both stories. He said the coverage was an example of one of his chief goals during his early time at CNN, which is to expand the definition of news that it covers. CNN's focus had drifted too much toward Washington-oriented stories over the past decade, he said. One of the things he's done is get rid of the "CNN(equals)politics" promotional tag that had been used.
While CNN's coverage of both Gulf Wars played prominent roles in putting the network on the map, Zucker said the O.J. Simpson trial and the rescue of Baby Jessica, the girl stuck in a well in Texas in 1987, were also memorable markers.
"We cover both what's important and what's interesting, and it's the mix of things that makes CNN great," said Zucker, the former NBC Universal president.
The network's extensive coverage this year of what became known as the "poop ship," a disabled cruise ship whose bathrooms stopped working, was also the target of critics.
Zucker also said that a criticism that CNN has not had enough conservative points of view on the air is a fair one and he's working to correct that. He mentioned the hires of Newt Gingrich and S.E. Cupp as conservative voices for the revived "Crossfire," which will begin airing this fall.
The CNN chief's face drooped slightly during an appearance, and he said he is suffering from Bell's palsy, a disorder that has left half of his face paralyzed. That is usually a temporary condition and he said he expects it to go away in a couple of weeks.