The 30-year-old made an immediate impact during his initial loan spell last term, claiming the Premier League Player of the Month award for August before contributing two goals and six assists across 22 appearances in all competitions.
However, his campaign was cut short by a foot injury suffered in January.
"I had a perfect time here for the first six months, then I stayed around after I got injured. I’ve been watching all the Everton games in pre-season and since the season started," he said.
Grealish, who joined Man City from Aston Villa for a reported fee of £100 million in 2021, has collected three Premier League titles, an FA Cup, and a Champions League during his time at the Etihad Stadium.
He is excited to work once again under David Moyes at Everton.
"I’ve had certain managers in the past where I feel I’ve played my best football under them – and he falls into that category, for sure," Grealish said.
"Now I feel ready to go. I'm ready to start training tomorrow and prepare for the games."