Who'll do Steve's jobs now? Apple hopes many brains are as good as one

The man who has replaced Steve Jobs as the chief executive of Apple promised one thing above all else in his first missive to shellshocked employees and supporters: "Apple is not going to change."

Tim Cook's emphatic statement was both fundamentally true and utterly impossible at the same time, because Mr Jobs' retirement robs Apple of the man who combined more roles in his one job than most executives fill over an entire career.

Mr Jobs has been Apple's visionary leader – the "gravitational pull" that holds the company together, in his own words – and its design guru; he has been the human extension of the Apple brand and its public marketer-in-chief; and he has been a micromanager willing to swoop in at every level of the company and terrorise his employees into perfection.

Which is why the focus yesterday, the first day "After Jobs", was on Mr Cook and on the team of executives who now report directly to him. This is the "deep bench" of executives that Apple has often boasted about but rarely pushed into the limelight.

Mr Jobs is staying on as chairman, but relinquished day-to-day control to Mr Cook on Wednesday night, admitting that he would not be able to return from the medical leave he took in January. Having battled pancreatic cancer in 2004, and undergone a liver transplant in 2009, he had appeared to defy medical odds in the past, but this time it was not to be.

"Steve has been an incredible leader and mentor to me, as well as to the entire executive team and our amazing employees," Mr Cook said in his memo to staff. "I want you to be confident that Apple is not going to change. I cherish and celebrate Apple's unique principles and values. Steve built a company and culture that is unlike any other in the world and we are going to stay true to that – it is in our DNA. We are going to continue to make the best products in the world that delight our customers and make our employees incredibly proud of what they do."

Mr Cook was Mr Jobs' hand-picked successor, an Alabama-born son of a shipyard worker who has impressed Apple's investors and those in the technology industry by revolutionising the way the company manufactures its products since joining in 1998. He is a workaholic business school graduate, whose style could not be more different from Mr Jobs. Whereas Apple's founder is prone to explosive, four-letter outbursts, Mr Cook is calm but firm; where Mr Jobs makes decisions on gut instinct, Mr Cook is more likely to be found interrogating mind-bendingly complex spreadsheets full of data. In the words of one former Apple executive yesterday, "he makes the trains run on time".

While the fact that Mr Cook was named by Out magazine at the top of its list of most powerful gay people adds some interest to his personal profile, he has not cultivated the cult of personality that Mr Jobs commands at Apple. Instead, Mr Cook is likely to rely on other executives more closely associated with the products and designs that Mr Jobs personally debuted on stage when he summoned the world's media to his product launches. The team includes the British product designer Jonathan Ive, who is vice-president of industrial design and the man whose gumdrop-shaped iMac set Apple on the road to recovery after Mr Jobs returned from exile in 1996. Phil Schiller, the worldwide product marketing chief, is also likely to take a bigger role, having often played sidekick to Mr Jobs at those product launches. Eddy Cue, who runs Apple's internet services, has also stood in for Mr Jobs, most notably when Rupert Murdoch launched his iPad-only newspaper, The Daily.

A question remains over who, if anyone, from that top management tier will fill the role of descending on product developers to demand changes to imperfect prototypes, and whether collectively they will have the ability to bet the company on potentially world-changing new technologies, as Mr Jobs did not once but many times.

Shelly Palmer, technology consultant and founder of Advanced Media Ventures, said: "Apple is a religion, it's not a company, and we know that cults and religions continue beyond their founders. Steve Jobs had a profound effect on the corporate culture and the management bench has worked for him for a very long time, so they are all imbued withthat culture. Steve did not draw the drawings, he approved them. He did not build the prototypes, he approved them. The execution of that culture is not just about one man, it takes teams of people, and thousands of employees."

How to replace the biggest brain in computing

The operations guy - Tim Cook

Apple's new chief executive has no plans to fill all of Steve Jobs' shoes. Together the two men had revolutionised the way the company manufactures its products, outsourcing in emerging markets and building a cheap, efficient and fast supply chain able to keep up with exploding demand from consumers. That will remain his focus, along with speaking more softly to investors than the abrasive Mr Jobs ever managed. Where Mr Jobs cultivated an internal cult of personality around the chief executive post, 50-year-old Mr Cook will lean more heavily on others.

The design guru - Jonathan Ive

An Essex boy transplanted to Silicon Valley, Jonathan "Jonny" Ive is regarded as one of the leading product designers of his generation. From the curvacious iMac and the slinky MacBook Air to the simplicity of the iPod, Mr Ive's minimalist designs have touched millions of people's lives. He and Steve Jobs were in synch about the need for Apple's products to be minimal, simple and easy-to-use; while Mr Jobs had the final say on everything, Mr Ive offers continuity in his role as head of industrial design.

The marketing man - Philip Schiller

Nothing says Apple like the sight of Steve Jobs, in his black turtle neck and jeans, pacing a stage and declaring that, once again, Apple is about to change the world. No other chief executive has been so closely identified as the marketing face of his company, and his departure robs Apple of a major draw for its super-hyped product launches. Philip Schiller, the Boston native who is a 17-year veteran of Apple and currently its worldwide marketing chief, sometimes does the product demo while Mr Jobs speaks, but now he must step out of his old boss's shadow.

The techie - Scott Forstall

Steve Jobs was a stickler for ensuring that Apple's hardware and software worked seamlessly together – even to the extent of descending on outside app developers for the iPad to instruct them on improvements – and the software side of the business now rests more heavily on Scott Forstall's shoulders. An employee at Mr Jobs' other company, NeXT, which Apple bought in the Nineties, Mr Forstall launched the Leopard operating system for the Macintosh and then, his crowning achievement, the operating system for the iPhone.