For a man with the herculean job of reinventing the venerable news network CNN, one of Jeff Zucker's first moves was a surprising blast from the past.

After years of being off-air, the booming tones of Star Wars actor James Earl Jones were back and announcing the channel's once-famous tagline. "This is CNN!" pronounced the voice of Darth Vader.

But anyone thinking that Zucker, 47, one of American television's best known and most hard-nosed executives, would be embarking on a wholesale journey back into CNN's hallowed past would have got a nasty shock.

Though he has officially been in the job for barely a week, Zucker has already taken a scalpel to the channel's roster of stars, sending famous names packing and bringing in fresh faces. He has signalled he intends to take the channel on a new path – less serious news, more entertainment and sport. More personality among its anchors and less po-faced political analysis.

To some that will be a shock. The concept of US cable news on a 24-hour nonstop cycle was invented by CNN 33 years ago when the channel was launched by media mogul Ted Turner. Since then Fox News and MSNBC have popped up domestically while the BBC and Al Jazeera, and a host of national rivals from countries such as Russia, China, Germany and Iran have also emerged with 24-hour networks.

Yet CNN is now struggling in its own backyard. While the international version remains ubiquitous in hotel rooms the world over, its US incarnation is fighting to remain relevant in the genre that it invented. It regularly languishes in third place in the ratings behind Fox News and MSNBC. Its style of news has become a joke for media savvy comedians such as Jon Stewart, who mock its struggle to make its voice heard in the increasingly crowded US broadcasting landscape. Indeed, with Al Jazeera preparing to launch a US channel, there is a fear that CNN may soon end up fourth in the US ratings.

To put it mildly, Zucker has a tough job ahead. "People are going to say he is just rearranging deckchairs on the Titanic," said Jack Lule, a journalism professor at Lehigh University, Pennsylvania. "He is just shuffling things around in a situation where the ship is still sinking. It is hard to imagine a world without CNN, but it is also hard to see what he can do."

Changes at CNN have already been tried. This is, after all, the channel that gave rightwing firebrand Glenn Beck his first big break on national TV. It is also the channel that has hired former British tabloid editor Piers Morgan for a primetime role as one of its key hosts and interviewers. Indeed Morgan is perhaps the high-profile symbol of what CNN is trying to change into: a channel that is desperately trying to create headlines and be part of the conversation, rather than a simple chronicler of major world events.

Only last week Morgan appeared as a guest on a celebrity chat show hosted by Chelsea Handler. The pair's interaction rapidly disintegrated into a bickering argument over who could insult the other the most. "Either you've had plastic surgery or a makeover, as you look really hot today," Morgan told his host. Handler gave as good as she got. "You are so annoying, you are so obnoxious and you wonder why everyone hates you," she said. The spat ended up with Handler telling Morgan: "You can suck my ass!"

That sort of publicity and behaviour would once have been considered a disaster for CNN, which has historically wanted to be viewed as the New York Times of American broadcasting: serious, sober and the first choice of policymakers. But no longer. Indeed Morgan, despite a poor ratings performance since joining the channel, seems likely to herald the new style of CNN that Zucker is aiming to build too. The pugnacious journalist is exceptionally good at getting his show talked about. During the recent media debate in the US over gun control in the wake of the Newtown school shooting Morgan did not shy away from loudly pronouncing his own opinions on the issue, including having a spat with rightwing radio host Alex Jones.

Indeed, as Zucker swung his axe, the new shape of CNN began to emerge amid the hirings and firings. Out went some of the stodgy old faces known for their political analysis in the shape of Democratic consultant James Carville and his Republican wife, Mary Matalin. Joining them through the exit were fellow political commentators Erick Erickson, Bill Bennett and Maria Cardona. All had been heavy on the weighty political talking points, light on the fun side of news.

Coming in were Chris Cuomo and Jake Tapper – both being poached from network television. Zucker, who rose to fame as the force behind NBC's hit morning programme the Today Show, appears to be trying to repeat that trick at CNN. Forces are being taken out of CNN's evening prime time and sent to the morning hours. Current evening host Erin Burnett is set to switch from evening to morning, to give a female partner to Cuomo and likely to oust the respected journalist Soledad O'Brien, whose reporting has won accolades but not an audience. "It does seem that an extended hard news show in the evening is not what people want any more," said Rick Edmonds, an expert at the Poynter Institute.

Zucker has a history here. The man who rapidly rose from a young producer on the Today Show in his 20s to heading NBC Universal – where his responsibilities included managing a theme park and a movie studio as well as TV interests – is known for trying to balance serious news with entertainment. That magic formula is what Zucker is trying to go for as he shapes CNN for a 21st-century media environment. Big names he is rumoured to be courting to come to CNN now include mainstream daytime TV stars such as Matt Lauer and Katie Couric.

Yet it will not be easy. The brand of CNN, which still generates millions of dollars in profit despite its poor ratings performance, remains hard news. Though it languishes behind Fox and MSNBC in the ratings every day, it often rises to the top when major news stories occur. As elections happen, wars break out or natural disasters strike, Americans switch off the talking heads of its rivals and tune in to CNN for its huge network of on-the-ground reporters and access to reporting from abroad. "CNN does really well with breaking news. It has a problem in that people stop watching when there is no breaking news," said Professor Robert Thompson, an expert in American TV at Syracuse University, New York.

In fact, CNN's – and thus now Zucker's – problem is not that Americans hanker for a different kind of news, or a different kind of presenter, or even a different time slot to watch it. It is that many of them these days do not want to watch news at all. They want opinion.

Fox News and MSNBC have not outshone CNN by the breadth and depth of their reporting or by investing in reporting talent around the world. Instead they have invested heavily in political branding with big-name hosts espousing their viewpoints and having debates with panels of guests who – more often than not – share those opinions. News is not made or revealed; it is talked about.

It has made stars of Fox News anchors such as Sean Hannity and Bill O'Reilly. Experts say the phenomenon is a sign of the atomisation of the viewing market as, with a plethora of channels to pick from, Americans are increasingly able to simply choose a news channel which will just present ideas they already agree with. But for CNN there is a problem. With Fox and MSNBC already occupying the right and left of the political spectrum, there is nowhere obvious for CNN to go. For CNN, it seems, adopting an ideology does not seem an option.

Some people say it is a good thing for the health of American journalism. "I am glad they have not staked out an ideological position and become all shouty. It provides a base of old-school reporting," said Thompson. But CNN's masters are no longer happy with last place in the ratings. Some experts think it needs to think radical. "They should just come on air for big news stories and then rent out that broadcasting space for the rest of the time," said Lule.

Such an extreme move is not likely. Not yet. But there is no doubt revolution is in the air and Zucker is at its helm. "This is CNN," says James Earl Jones's voiceover again. But exactly what he means by that phrase is up for debate.