The England international hit the headlines after partying hard for days after City's Champions League success.
Teammates had to carry Grealish out of a hotel after a night out in Ibiza and the former Aston Villa skipper continued his celebrations during the club's parade through Manchester city centre.
Despite admitting he hadn't slept for 72 hours, Grealish did manage to sober up in time to join up with the England camp.
The 27-year-old was an unused substitute for Friday night's win against Malta but did feature as a second-half substitute in Monday's 7-0 thrashing of North Macedonia.
When asked if he had fully recovered from the celebrations, Grealish exclusively told talkSPORT: "Yeah, of course! I probably had one of the most enjoyable seasons of my life.
Read more on Man City
Oleksandr Zinchenko sends message to Manchester City after treble win
Shirtless Ricky Hatton gets on the beers ahead of Man City's Champions League clash
"The second half of the season, I played a big part in something that will go down in Man City history.
"Last weekend was the best weekend I've ever had. I'm still trying to come to terms with it. I've been on such a high the last week.
"I feel good. I trained on Wednesday and Thursday, and felt alright. Obviously, Saturday and Sunday, I felt good."
The Manchester City star came in for criticism from some quarters over the extent of his celebrations ahead of the Three Lions' key Euro 2024 qualifiers.
Most read in Football
Arsenal make new Havertz bid, Grealish opens up on wild celebrations, Saudis want Son
Chelsea confirm signing of Christopher Nkunku from RB Leipzig in £63million deal
Arsenal make new and improved bid for Havertz but it's still below Chelsea's valuation
Arsenal launch £30million bid for Manchester United target with club hopeful of compromise
However Grealish insists he has no regrets and pointed to the magnitude of his side's success as justification for his antics.
"Not really," he replied when asked if the criticism bothered him. "I'd done something that comes around once in a lifetime. The last time it was done… I don't know when Man United did it, but it hasn't been done for ages.
"So why not celebrate like that? Everyone was with me. I wasn't on my own, going out with my friends. I was with the whole team.
"We enjoyed ourselves on the Saturday, Sunday, Monday. I had the best weekend of my life. I'd just won the Champions League and I was so emotional after it.
"I was probably on the biggest emotional high I've ever been on. The manager didn't tell me, but I knew I wouldn't play on the Friday.
"I came on today and I felt good. Whatever you do in life, there will always be people in the background criticising you. It's part and parcel of life.
"My full priority is with England. That's why I was in camp on Tuesday night. Obviously I had a good weekend, it was the best weekend of my life."