To mark his remarkable achievement Williams pledged to "party" in a post-victory press conference which the 43-year-old delivered in just a towel.
Williams said: "It's unbelievable".
"To be honest, if I won this next year, I'd do it again". "I'm going to keep my mouth shut next year, not say anything stupid and end up like this!"
Asked how he would celebrate, Williams - who tweeted from a kebab shop at 2am on the morning of the opening session - said: "Last time I won it I think I had half a pint of milk and went to bed".
I don't know enough about snooker to interpret for you the circumstances or specifics of the game that lead to his victory in a way that wouldn't sound incredibly forced and likely very incorrect but, I can assure you, he sure hit those balls better than the other guy, then he got naked.
Hearn, chairman of World Snooker, stood beaming at the back of the room. What an advert for the sport.
He added: I'm so happy I won.
However, Williams pulled through and won 18-16 by the end of the match. The two-time former world champion from Wales recharged his batteries with a couple of hours sleep to return to the table to get the upper hand over Scotland's Higgins on Sunday. Williams needed another opportunity and gave himself one early in the next frame.
The Welshman held off John Higgins' fightback to triumph 18-16 - 15 years after his last success at the Crucible. The Welsh potting machine, as he is nicknamed, won the World title in 2000 and 2003, before having a drought of wins before his incredible 2017/18 season.
"If there is another world title in me, that would be unbelievable".
"I enjoyed that one more than the other ones I've been in".
"It feels a little bit uncomfortable at the minute", he laughed. And deservedly so really, it's a big occasion for me. I've done something I never thought I'd do again'.
Williams was "away in my caravan, getting drunk and watching it on TV" when his fellow cuemen contested the 2017 tournament.
He joins Mark Selby as a three-time Crucible champion, behind only Stephen Hendry with seven, Steve Davis with six, Ronnie O'Sullivan with five and Higgins with four. "The last frame was just a joke there for him to play that well under that pressure".