The 29-year-old player was sacked by his club Wigan Athletic within an hour of him starting a new life behind bars.
The £5 million striker, who had been drinking to celebrate his wife's pregnancy and scoring a winning goal earlier, launched the unprovoked attack on a university student after repeatedly being ''cold-shouldered'' by women in the packed Soho Revue Bar.
The court had heard that when they too ''recoiled'' from his touch he turned back to the student telling her: ''Don't you know who I am? I'm a millionaire.''
She claimed: ''He started poking me in the head, pushing my temple like he was enjoying it, repeating, 'Not even in my league'.
''I kept on repeating, 'Take your multi-millions and leave - no one cares. Just get away from the table'. I felt tiny. I felt really embarrassed.'' He then punched her to the floor.
Two other revellers - one actually holding his arm - were also sent flying.
As his victim was helped to her feet, blood poured from her shattered nose and cut lip.
The £35,000-a-week footballer, from from Waltham Cross, Hertfordshire, will now lose more than £1 million following the termination of his contract.
The jury at Southwark Crown Court took just under four hours to convict him by a 10-2 majority of sexually assaulting the 20-year-old and causing her actual bodily harm.
King, branded ''arrogant'' by Judge Nicholas Loraine-Smith, was told that in addition to jail he would have to register as a sex offender for seven years, pay £3,125 compensation to his victim and £1,800 prosecution costs.
Following the court hearing Wigan Athletic chairman Dave Whelan announced King had been sacked.
He said: ''We have to follow the rules and regulations, which means we will have to give him 40 days notice that his contract will be cancelled.
''He is absolutely sacked - we will not tolerate football players who get sent to jail for 18 months. As far as we are concerned, he is finished with football at Wigan Athletic,'' he told Sky Sports News.
After convicting King, the jury learnt the Jamaica international had 13 previous convictions, including violence against women, dishonesty, drink driving and other motoring offences.
As his 20-year-old victim sat at the back of the court, the judge, said: ''I appreciate this will cost you an enormous amount of money, but it is difficult to be sympathetic when you were boasting about your earnings in the way you did.''