But what's known about the man who replaces the quintessential Guardianista, Carolyn McCall?
The 43-year-old Miller was not top of mind, externally at least, after McCall shocked the media industry with her decision to step down in favour of a low-budget airline in March.
In fact, very few people appeared to know of Miller outside GMG before he was named interim chief executive in May, effective upon McCall’s departure.
In the ensuing speculation surrounding the top job, muted though it was, Miller was easily overshadowed by other names thrown into the mix, including those of John Cresswell, ITV's former interim chief executive, and even Guardian News & Media's own Tim Brooks.
The appointment process
Miller was given the top job following what has been described as a "rigorous" appointment process, led by a sub-committee comprising of Amelia Fawcett, chairman of GMG Group, Liz Forgan, chairman of the Scott Trust, and independent GMG directors John Bartle and Neil Berkett.
The committee was advised by Spencer Stuart, a global executive search firm.
The appointment was agreed by the full board, including Alan Rusbridger, editor-in-chief of Guardian News & Media, Tim Brooks, managing director of Guardian News & Media, and Stuart Taylor, chief executive of GMG Radio.
The board reportedly came to the unanimous decision that Miller had the "right qualities for the job", namely "financial acumen, experience of leading M&A activity and a strong relationship with Apax", crucial for further negotiations with the group which part owns B2B publisher Emap with GMG.
Having been part of the group for a number of years, he is also credited with knowing the cyclical and structural changes that continue to dog the media business and, just as importantly, how GMG's board operates, with its subsidiaries and sole shareholder, The Scott Trust.
The unknown jewel in the crown
An accountant by design, it’s fair to say his profile is non existent among the UK media agencies. Yet he brings valuable experience to the role, including big client expertise garnered from time spent at Pepsi and Procter & Gamble.
He’s made an impression beyond that of ‘good bean counter’ since becoming chief financial officer at GMG in August 2009.
In an internal memo, Fawcett highlighted Miller's "combination of attributes" that make him "ideal for the role". Among them is his time as chief financial officer of Trader Media Group.
During his six year tenure at TMG, the publisher of Auto Trader and Ad Trader, GMG’s new chief played a key role in the group’s transition from a print to digital business.
Approximately 90% of TMG’s £100 million-plus annual profit is reportedly generated through its digital channels today, and Fawcett calls it "one of the most successful examples of print-to-online transition in the world". She’s not alone in her praise.
Simon Waldman, GMG’s former group director of digital strategy and development, now at LoveFilm, believes Miller is simply the best man for the job.
"He’s a got a really good brain and truly understand the dynamics of the digital transition taking place across the business," he said.
In addition to his understanding of the structural changes, Waldman points to his knowledge of GMG’s partnership with Apax, and general acquisition expertise.
"This will be critical to the future success of GMG," he added, as the group looks to broaden and strengthen its core interests.
Numis media analyst, Lorna Tilbian, agrees. "He was the jewel in the crown at Auto Trader and has a proven strategic track-record," she said.
The leading industry analyst also believes he can shore up GMG’s financial position, following a year of record losses of £171m.
"If you can count the beans, you can probably find them as well," reasons Tilbian. By way of example, she points to Russell Taylor, the successful chief executive of ITE Group who used to be CFO. Similarly BSkyB’s chief executive Jeremy Darroch earned his stripes as CFO.
Both examples appear to bode well for GMG, although you do not need to search too far to arguably find examples to the contrary: ITV’s Charles Allen and Scottish TV’s Andrew Flanagan?
But what of the claim the accountants have taken control of The Guardian, and the implication that this will be somehow detrimental to its creativity and personality?
"That is an entirely wrong misconception," according to GNM’s former marketing director, Marc Sands.
Now head of marketing and media at the Tate galleries, Sands called the new chief executive "very impressive" and said his direct approach and strategic insight would have made him the favourite internal candidate.
"You want someone like Andrew Miller to be leading GMG," he added. "The role of GMG is very different to GNM. It’s a holding company that manages the finances, it does not operate at any micro-level with its subsidiaries, including The Guardian."
According to Fawcett, Miller has already demonstrated through the recruitment process that he has a clear vision for the future of GMG. The jury’s out on whether he truly has the ability, desire and vision to lead GMG through the next stage of its development, but he’s certainly not short of 'internal' support.