However, he looks to have embraced the life-changing reality that he will soon become a father for the first time by enjoying a more relaxed break.
Earlier this month, Grealish and his partner, Sasha Attwood, announced that they were expecting their first child together.
Grealish and Attwood - who has worked as a model for big brands, including L'Oreal and Pretty Little Thing - have reportedly been dating since they were teenagers growing up in Solihull.
They will both be expecting significant change in their relationship early next year when the baby arrives, and Grealish seems to be preparing already.
According to the Mail, the PS100million man has ditched the days of being pictured hazy-eyed and stumbling out of nightclubs and bars, and lying in a drunken state on the pavements of Tenerife.
It's claimed he appears to have enjoyed a calmer off-season, during which he was spotted soaking up some world-class tennis at Wimbledon.
On the day England underwhelmed in a 0-0 draw against Slovenia in Group C, Grealish is said to have been putting in the work at the City Football Academy.
Grealish made just 10 Premier League starts last term as Pep Guardiola's side pipped Arsenal for a second successive year to lift an unprecedented fourth title in a row.
He featured 33 times in all competitions but managed to contribute just three goals and three assists.
"I was shocked because I know what Jack can do. [But] was I shocked because of the players that he [Southgate] has brought in? No, because I think they're all at a great quality and they've all had fantastic seasons," Walker told ITV Sport earlier this summer.
"I think Jack would be the first one to say he could have had a better season. I think he's come out publicly and said he could have had a better season.
"So what does a manager base it on? Form or people that he knows have had good tournaments or a good season the season before? You're here on merit. And I believe it should always be like that."