O’Sullivan, having been outstanding throughout the tournament, secured his third title by completing an 18-8 success over Ali Carter at Sheffield’s Crucible Theatre.
O’Sullivan said: “I’m just happy to have won, it was tough. When you get ahead, you are always thinking at the back of your mind, if you lose it from here, it is going to be a killer.
“Sometimes it is better when it is closer, sometimes when trying to protect a lead it is hard.
“I wasn’t playing fantastic every session, but you don’t need to be to win this. It is about doing it in some sessions.
“Ali and I are disappointed not to put on a better performance but we love the pressure and excitement at The Crucible.”
O’Sullivan now hopes to win more titles, but admits he might still consider taking “a break”.
He added: “Hopefully it is not the last, hopefully there are a few more to come.
“I said I would like to win more, but it is quite well documented that I struggle with the game.
“Sometimes I think it would be good to go out on a high. I will have a think and it might be a good time to take a break.”
Despite his defeat, Carter still enjoyed a fine tournament and tied O’Sullivan for highest break with a maximum 147.
Carter said: “I am pleased to get to the final. I am disappointed not to perform at my best but it is very tiring.
“Ronnie made it very difficult. His safety was brilliant and the better man won on the day.
“The top eight in the world, a maximum and the final of the World Championship — I would have taken that at the start.”
Not even a male streaker, who entered the auditorium at the start of the final session and spreadeagled himself under the match table, could knock the Rocket out of his stride.
O’Sullivan was never seriously tested in a low-key affair after his memorable performance against seven-times winner Stephen Hendry in the semi-final.
O’Sullivan becomes only the fourth player to complete snooker’s most coveted treble.
O’Sullivan joined Steve Davis, Stephen Hendry and Mark Williams in winning the UK Championship and the world title, in addition to clinching the number one spot in the rankings in the same season.
He has become the first player to be world number one on three separate occasions, having previously held the accolade in 2002-03 and then again from 2004-06.
And O’Sullivan, 32, is the first player aged over 31 to lift the world title since rank outsider Joe Johnson disposed of Steve Davis 22 years ago.
O’Sullivan has also topped the prize money list for the fifth season running in earning £638,350 from nine tournaments — including £250,000 for winning the world title.
He also had half a share of the maximum break prize of £157,000 — shared with Carter, who also pocketed £125,000 for finishing runners-up in his first ranking final.
O’Sullivan led 11-5 going into the second day of the final.
But what will be galling for Carter is that O’Sullivan failed to produce anything like the standard he had shown in demolishing Hendry 17-6 in the semi-finals.
O’Sullivan did compile one century and 10 other scores over 50.
But Carter, a former practice partner of O’Sullivan, will be massively disappointed to have failed to make the most of several decent opportunities which came his way.
O’Sullivan went into the final session needing to win only two of the remaining 11 frames to secure the title after triumphing 5-3 in the afternoon.
A break of 69 in frame 25 left Carter needing snookers and took O’Sullivan to the verge of the finishing line.
And it was all over in the next after Carter missed a blue into the middle pocket and let in O’Sullivan to seal his victory.