The 20-year-old has moved to the KCOM Stadium on a season-long loan deal sanctioned by former Tigers chief Marco Silva.
Bowler started his career at Queens Park Rangers and made his Championship debut on the final day of the 2016-17 season against Norwich City.
He moved to Everton later same summer for an initial £1.5m and has since helped the club's Under-23s lift the Premier League 2 title.
"I am very excited to be here because it is a massive club," said Bowler, who is expected to feature when City travel to Mansfield Town this Saturday. "As soon as I heard of Hull's interest, I wanted to get the move through. I am thankful to be here now and I am raring to go ahead of the forthcoming season."
Bowler joins Queens Park Rangers goalkeeper Matt Ingram and Gillingham striker Tom Eaves in signing for the Tigers ahead of the new season.