It brings to a close one of the most incident-packed careers in cricket history, laden with thrilling innings, unseemly spats and series transformed.
But if you are looking at his exit now and thinking it might all have turned out so differently, imagine how things might have been if Pietersen, who left his native South Africa early in his cricket career to start a new life in England, had stayed put.
How would it have affected the history of cricket?
Here we take a (not always serious) look at the way history could have been rewritten. The quotes are not real, but we lean on the history of the last 10 years in cricket to see where paths might have diverged.
Disenchanted by his chances of succeeding in South Africa because of a quota system that he felt unduly hindered his chances of progression, Natal-born Pietersen considers leaving his homeland and joining Nottinghamshire.
But after dalliances with the county game, he is convinced to stay by KwaZulu-Natal, and the off-spinner who bats a bit is encouraged to work on his batting.
He improves to the point that, by 2004, he is on the fringes of a call-up to the national side.
Though he has developed significantly as a cricketer, Pietersen has not yet been fully embraced by the South African public for his flirtation with England.
He gets his chance to play for South Africa in the 2004/5 series against England, and the Barmy Army choose to test his temperament with a string of chants and songs aimed at what they call the "wannabe Englishman."
But in the bear pit, Pietersen thrives, scoring a mountain of runs and taking the Man of the Series trophy as South Africa romp to a 5-0 series triumph, atoning for the Test series they lost.
In a show of loyalty that some brand tacky, Pietersen gets a Proteas tattoo to clear up his allegiance.
England are enjoying their best period of Test cricket in recent history, and after 18 miserable years of losing to the Australians, hopes are high that they can stun the tourists.
A thrilling series grips the nation, and the home side take a 2-1 lead in the final Test at The Oval.
But after holding their own in the first innings, the burden of expectation proves too much. With veteran batsman Graeme Thorpe kept on for one series too many, England are exposed, and Michael Vaughan's men lose the Test. Australia retain the Ashes by the skin of their teeth, and England's wait continues.
"We just needed a batsman to go in unafraid on the final day," reflects Vaughan afterwards. "I guess too many of us were battle-scarred from the other series defeats."
Meanwhile, Pietersen's progression with South Africa is seamless, with the likes of Zimbabwe and West Indies laid to the sword. He scores centuries early on in his career and is quickly identified by the South African national press as the player who can help take the Proteas to the top of the world game, with a home-and-away series against Australia looming.
Nobody has been able to dislodge the Baggy Greens from the top of the world standings for over a decade, but South Africa's line-up, under the captaincy of Graeme Smith and blessed with the likes of Pietersen, Kallis, Pollock and Co., are hotly tipped to be the side to challenge them.
They lose the three-Test series narrowly in Australia despite two centuries from KP, but they win the return in early 2006 by a 2-1 margin, thanks to a stunning 158 from Pietersen on the final day of the series at the Wanderers.
England, meanwhile, are beset by injury problems and personnel changes after a miserable winter in Pakistan and India.
Despite that, Andrew Flintoff leads the touring party for the Ashes with high hopes that the 2-2 draw in 2005 and Australia's loss in South Africa bodes well.
It doesn't—England are thrashed 5-0, without even the consolation of a single batsman standing up against the onslaught.
Coach Duncan Fletcher is sacked mid-series, while Andrew Flintoff resigns the captaincy after Perth and passes it to Andrew Strauss.
South Africa's reputation as chokers has cast a long shadow over them in international tournaments, but that tag is laid to rest in emphatic style in 2007 as they first win the World Cup and then follow it up with victory in the inaugural World T20 on home soil.
In the World Cup in the West Indies, the Proteas make a slow start, but in the semi-final against Australia, their recent record helps them mentally. Pietersen, sent in to open with Graeme Smith, puts on 105 for the first wicket, and the South Africans build a score of 280, which they are able to defend.
Sri Lanka pose little threat in the final, and the South Africans win in the dusk.
Later in the year, the burden of expectation sits a little easier at the World T20, although there is concern in the Proteas' final group game as India rip through their top order.
Pietersen and Mark Boucher fight the Proteas' way out of trouble and from 31-5 they eke out an unlikely victory which sees them through to the knockout stages at India's expense.
The rest is history.
As exciting as the World T20 turns out to be, India's group-stage exit dampens their enthusiasm for the event.
A young hotshot with the Board of Control for Cricket in India proposes a domestic T20 competition called the Indian Premier League, but he finds there is little interest in the event, either from the BCCI or the Indian public at large.
Plans are shelved before a ball is ever bowled.
Graeme Smith has enjoyed an unprecedented spell of success as the South Africa captain, but tensions between the left-hander and Kevin Pietersen reach breaking point in 2008.
With tension hovering over the team during their tour of England, a trough in form for the skipper is enough to prompt his sacking midway through the series.
Pietersen is a surprise pick to take the job, but he responds by scoring a century in the final game. The England crowd boo him mercilessly, but KP appears to relish it.
"I've never felt so loved," he gushes after a hundred in the final Test.
Pietersen's appointment as captain proves a disaster, fighting with his coach, Mickey Arthur, and reportedly falling out with many of his team-mates as South Africa collapse to a 3-0 defeat in Australia, then repeat the feat on home soil early in 2009.
A clamour builds in South Africa for Smith to return as captain and for Pietersen to be frozen out of the team.
With no results to fall back on, KP is dumped from the side for the promising Hashim Amla, and with his international career seemingly at an end, he signs up with Hampshire for his first season of county cricket in the summer of 2009.
While KP scores centuries for fun at domestic level until a knee injury ends his summer prematurely, England, who have already passed the captaincy on to Alastair Cook, take on Ricky Ponting's Australia in the Ashes.
An injury early on in the contest For Andrew Flintoff prompts him to call it quits midway through the series, and Australia come away 2-1 victors.
"I could probably have played on with the right mix of injections," Flintoff opines, "but it's a lot of pain to go through to lose one last time."
South Africa under Smith are resurgent, and KP is quickly erased from Proteas history.
They conquer all, home and away, bouncy tracks or subcontinental turners, and rise to the top of the tree in all three formats, pocketing the World T20 trophy for a second time in 2010.
Arthur is credited as the mastermind behind it all, so it is something of a surprise when in 2010 he is persuaded to leave the post of South Africa coach and take charge of England.
England have been through a multitude of coaches and captains and decide they must hire the best, whatever the sum of money involved.
Arthur tries to splash a little of his magic on the team, and Ian Bell's charges head out to the 2010-11 Ashes with renewed hope.
England quickly fall into a hole in the first Test, however. They score 260 batting first at the Gabba before Australia make 481 in reply.
Alastair Cook is bowled for a first-ball duck in the second innings, when really only a double-century will do.
Arthur is furious, insisting that he'd told him to score precisely 235 the previous night, and Cook simply hadn't done his homework.
Cook is dropped, but Arthur's tenure never recovers from the ensuing press field day. Homework-gate, as it comes to be known, defines his spell in charge, and he doesn't survive in the job after a disappointing World Cup in India.
A host of other coaches are tried, but without success. County cricket is overhauled annually as coaches look to reignite the English game, but the only consistent thing about domestic cricket in England is Pietersen, who week in, week out, bludgeons all-comers as Hampshire bag a hatful of titles.
In the summer of 2013 and the following winter, England and Australia lock horns twice. There are low expectations from the Barmy Army, the press corps and even the England players themselves.
A team led by Matt Prior are beaten 4-0 at home, with only rain saving them in the other match.
In Australia, things are no better, as the Baggy Greens record a third straight 5-0 Ashes whitewash Down Under.
Talk during the series turns to drastic solutions, and having now gone almost 30 years without winning the Ashes, the press are debating whether the series should any longer have iconic status.
In a series of clandestine meetings in the aftermath of that series defeat in February 2014, new director of England Cricket Paul Downton discusses the way forward, and among the more drastic courses of action they consider is to select a 33-year-old veteran who has recently completed his qualification period in England.
It is a move that would not have been countenanced had the situation not been quite so desperate, but Downton, in a carefully worded statement, says there is simply no choice.
Kevin Pietersen has been asked—and has agreed—to play for England.