It's kind of surprising and not surprising. Surprising because he's only 34, still young for a cricketer, and because he had been so adamant that he was not retiring. Not surprising, because his degenerative back condition always meant he would retire younger than most, and because over the past few months he has looked like his heart's not in it.
No-one in elite sport is universally loved even among among their team-mates, especially not while they're playing. Elite sportspeople are driven and competitive and this often makes them abrasive and inconsiderate. Still, Clarke seems to have copped more criticism than most considering his achievements. So, in the interests of fairness, here's six things to remember him by.
In the 2012 calendar year, the year after he took over as captain, he scored 2,400 test runs including three double centuries and a triple. He was like the energiser bunny, super fit, with supreme concentration, unthreatened by pace or spin, able to run up the steps to the dressing room after two days at the crease. He was Bradman reincarnated. Ricky Ponting experienced a late career renaissance just by following in his wake. The deeds of the greats of the past - Chappell, Border, Waugh - all paled beside him.
Before and after he was not quite so great. With one test to go in his career he has a touch over 8,000 runs at an average of just under 50, which is good but not as good as many other present-day masters. But it's none too shabby either and he can retire feeling pretty pleased with himself.
2. The Golden Generation
Clarke started his career as the youngest member of a great team. His team-mates in the early years included Hayden, Langer, Ponting, Gilchrist, Warne and McGrath. They swept all before them.
This generation of players was so dominant that the Australian selectors have been reluctant to let them go, even though in the last few years all that has been left are the understudies. Ever since Adam Gilchrist retired they have been loyal to Brad Haddin, notwithstanding a short preference for Matthew Wade and despite Haddin's up-and-down form with both bat and gloves. They have shown even less explicable loyalty to Shane Watson, the promising allrounder who is still promising at 34 without ever having quite delivered. They built their bowling attack around two veterans, Mitchell Johnson and Ryan Harris.
When they were worried about the batting for the 2013 Ashes tour they called in long-time opening batting bridesmaid Chris Rogers. The gamble was so successful they rolled the dice again in 2015 with Adam Voges, proving that if you have a big win at gambling the law of averages indicates you should go home right away.
Clarke, the only one of this number who was not an understudy, was the only realistic choice to lead them. It's not surprising that even his own superlative batting and tactical nous were not enough for this ageing B Team to match the feats of their predecessors. Still, Clarke can be glad he was not Brian Lara, the last scion of the West Indies great generation forced to play alongside bumbling mediocrities as West Indian Cricket crumbled. Clarke got to lead a decent team and they got some decent results. Steven Smith will have a much sterner challenge, with all but Johnson set to exit stage left after this series as rebuilding gets serious.
One of the reasons Clarke had reasonable success with a relatively modest team is that he is an astute tactician. Under his predecessor Ricky Ponting, fans and critics got used to scratching their heads as he made odd, paradoxical and sometimes downright stupid tactical decisions. His teams mostly won despite that because the players were so good.
With Clarke there were no tactical brain snaps. He set clever, well thought out fields, he made canny bowling changes, he declared at the right time, his choices at the toss were carefully considered. If his team lost, it was because the players failed to perform, not because the captain was a dill.
4. Lara and Kyly
Clarke was much maligned for his relationship with Lara Bingle, yet it is hard to see what he did wrong. He fell in love with a beautiful and vivacious woman. He missed cricket to support her when her father died, as any man should. When it became clear the relationship couldn't last he ended it privately, face to face, missing more cricket to do so. If she is a flighty drama queen that is hardly his fault.
You might have thought that his marriage to former schoolmate Kyly Boldy would settle all that down, but she is hardly less glamorous than Lara, although apparently much more grounded. The marriage has served to cement Clarke's reputation as a playboy with an eye for beautiful girls. Personally I think his detractors are just jealous that in his lifetime he could win the love of two such gorgeous women.
Still we all age. Clarke has shown he has a strong sense of family and of personal responsibility. I would be willing to bet that he will still be treating his wife with respect and dignity long after the bloom of their youth has faded. I don't reckon it's an accident that his retirement coincides with the impending birth of their first child. Who would want to travel the world hitting a leather and cork sphere with a lump of wood when the light of your life is growing up at home and you're missing all the best moments?
The one criticism of Clarke that does seem fair is that he has a very prickly relationship with his team-mates. This problem first hit the headlines when he had a fistfight with Simon Katich in the dressing room. I'm firmly with Clarke on this one. Mike Hussey was the designated singer of the team song, to be sung after each Test victory. No-one could leave the dressing room until it was sung, and it could not be sung until the designated leader said it was time. Apart from being a pretty dumb custom (and a stupid song to boot) in Hussey's hands the dressing room celebrations got longer and longer. Clarke had other plans. Mentioning it politely didn't work. He got cross. Hussey's mate Katich grabbed him by the throat. Clarke just wanted to have a life. Simon Katich needed to learn about work/life balance.
On the other hand, some of his conflicts show a level of inflexibility and even harshness which seems out of place in a leader. He was the main instigator of the final banning of Andrew Symonds, effectively ending his career. Certainly Symonds had disciplinary form but the final cause was his missing a team meeting during a rather pointless Top End series against a mediocre opponent. Not only that, but Symonds had a good explanation - he didn't know the meeting was on. It was supposed to be a free morning, so he got up early to catch the tide and was out on the water with his fishing rod when the meeting was called at short notice. He got disciplined for wanting to have a life. What's good for the goose...
Team meetings were once again at the root of the Homeworkgate saga in which Clarke also played a central role. Team members were supposed to submit some written tasks prior to a team meeting during an Indian tour. Some of them didn't, including then vice-captain Shane Watson and Mitchell Johnson, and all were suspended. It was hard to know whether to laugh or cry. That's not the way to build team spirit and get everyone working together.
6. Phillip Hughes
If we can be critical of some of Clarke's relations with team-mates, it's impossible to be critical of his response to Phillip Hughes' death. He was clearly shattered. He rushed to be at Hughes' bedside as he lay dying, visited his family at home and gave a moving, tearful eulogy at the funeral. As with the passing of Lara Bingle's father, he showed that he is a man his friends can rely on in a crisis. He may get the little things wrong, but when something big comes along he knows what to do.
For most of us, Hughes' death is in the past. It was sad but after all he was just someone we watched on TV. Not so for Clarke, who played with him at State and National level. Imagine that a long-standing workmate is killed in a workplace accident. From then on, every time you go to work you think of him. Every time you do the task which resulted in his death your hands shake. This is precisely what Hughes' death is for Clarke.
Initially, he was determined to soldier on. Despite his own back troubles he turned out against India the following week and scrapped his way to a century before snapping his hamstring. The determination kept him going through a difficult rehab and into the victorious World Cup campaign.
There is only so long you can grit your teeth and fight on. Eventually the sadness will gain the upper hand and the tears will flow. You come to understand that death is irreversible and that you can no longer see things the same way. Clarke still wears his black armband. I would be willing to bet that this grief is a much bigger factor in his recent poor form, and in his retirement, than he will ever admit.
***I know cricket is not that important. People are starving , millions are threatened by war, we are stuffing up the planet. What is a bunch of men hitting a ball beside all that? Yet what is life without art? What is it without play, without fun, without learning a skill for the pure enjoyment of the challenge? Michael Clarke has taken us out of ourselves as he performed his art on the world stage for more than a decade. He has given us a chance to admire his dancing feet, his deft timing, his sheer concentration and determination. He has made the near-impossible look easy.
Now it's time for him to move onto other things. May he go well.