O'Sullivan plays in a fast and attacking manner. He is a prolific breakbuilder and solid tactical player. He has stated his disdain for long, drawn-out games, saying that it harms the game of snooker. He is regarded as an excellent front-runner; by many other professionals. In previous years, he could become demoralized by being behind and not playing well, and was liable to lose several consecutive frames. He is right-handed but can play to a very high standard with his left hand and routinely alternates where needed. While not quite possessing the same power in his left arm, being ambidextrous enables him to attempt shots with his left hand that would otherwise require awkward cueing with a rest or spider.
When he first displayed this left-handed ability in the 1996 World Championship against Alain Robidoux, the Canadian accused him of disrespect. O'Sullivan responded that he played better with his left hand than Robidoux could with his right.He was summoned to a disciplinary hearing in response to Robidoux's formal complaint, where he had to prove that he could play to a high level with his left hand. He played three frames of snooker against former world championship runner-up Rex Williams, winning all three. The charge of bringing the game into disrepute was subsequently dropped.
In December 2006, in his quarter-final match of the UK Championship against Hendry, O'Sullivan conceded in dramatic fashion part-way into the sixth frame of the best of 17 match. O'Sullivan was leading 24-0 in the sixth frame when he threw in the towel, shaking hands with Hendry and referee Jan Verhaas before leaving the arena, to the amazement of spectators. O'Sullivan issued a statement later that day, apologising and saying that he would be "back on his feet fighting stronger and harder than ever very soon." On 31 May 2007, World Snooker fined him a total of ₤20,800 over this incident, and docked him 900 ranking points.
At the World Open O'Sullivan made his record 10th maximum break in the last frame of his match against Mark King, which he won 3-0. However, he had to be persuaded by referee Jan Verhaas to play the final black, as he had become aware that there was no distinct prize money for a maximum break in the tournament, but only a prize of ₤4,000 for the highest break. Even then, he played the final black in a nonchalant fashion.
O'Sullivan asked officials what the rolling prize had reached for
this week's Welsh Open when leading Barry Pinches 3-1.
And when told it was just ₤10,000 three-time event winner O'Sullivan,
40, deliberately played for the pink off the 14th red.
He then completed a brilliant 146 break at the Motorpoint Arena -
taking the black again off the final red to close out a 4-1 victory.
O'Sullivan said: I could have got on the black off that red,
and possibly got another 147. You never know, it can get twitchy.
But ₤10,000 - it's too cheap! It is a massive achievement getting
a 147 and it is worth more than that. Once it goes up I'll give it
another go.