The Man City star let his now-famous hair down the minute the final whistle was blown at the Etihad Stadium on Sunday, with his celebrations continuing throughout this week - and who can blame him?
He has jetted straight out to Ibiza, where he met up with Lineker [brother of Match of the Day presenter, Gary], who posted a picture of the two on Instagram, with the caption, 'Here he is…'
This came just a day after the club's title celebrations and open-top bus tour which took place on Monday, where Grealish was seen drinking beers and what appeared to be vodka cokes.
Every time he was handed the microphone he would leave the crowd in stitches - which included when he promised to buy jägerbombs for whoever met him at Manchester restaurant, Albatross & Arnold.
He later joked that Pep Guardiola only signed him because he got the better of Kyle Walker when he was playing for Aston Villa last season, something which had his boss in hysterics.
Bernando Silva and Grealish were then seen chatting during the celebrations, which led to the England international comparing Riyad Mahrez's poor performance to Newcastle man Miguel Almiron.
He said: "Riyad, take him off the pitch, as soon as possible. He played like Almiron."
However, talkSPORT's Simon Jordan wasn't best pleased with Grealish's behaviour, in particular his comment about Almiron.
He went on to lament the former Aston Villa man's behaviour, labelling the midfielder a 'moron' and his comments as 'arrogant' and 'lacking awareness'.
"The bottom line is it takes Jack Grealish back to where he belongs - in moron territory - engaging his mouth before he engages his brain," the White and Jordan host told talkSPORT.
"There's no problem with him having banter with his teammates, that's absolutely fine. If someone was to say he was taking the mickey out of Riyad Mahrez, you'd say it was banter, they've got that rapport.
"But if you take it out of another domain and you pick another player, single him out, and ridicule him because you think you're in a position to do so, where's that going to end?
"Someone somewhere is going to say, 'By the way, who are you?' What gives you the right to make that comparison? Why would you want to do it? Where does your arrogance stop and intelligence begin?
"I'm sure he meant it tongue-in-cheek, but why pick on an individual player?
"Obviously in the back of his mind, he thinks that player probably is not good, and that's his prerogative, but why does he need to do that to that particular player when Man City are talking about their success?
"Why does he think he is on a platform where he can look down on that player?
"Jack Grealish is a talented player, he's a long way from being a £100million player.
"He's incredibly fortuitous to be playing for a club like Man City that has enabled him to win a Premier League, because I don't think his contribution has taken Man City to that Premier League title.
"I think he's a bit-part player, so he would have been better served saying, 'Take me off the pitch' more.
"It's a lack of awareness."