The 20-year-old, who joins the Saddlers alongside Stuart Sinclair, James Clarke, James Hardy, and Elijah Adebayo, joined Everton's academy aged 10 and was named the Under-18s’ Player of the Season for 2016/17.
Jack followed up that successful campaign by signing his first professional contract in the summer of 2017, he helped David Unsworth's Everton Under-23s win a league and cup double last season and also featured twice in the Checkatrade Trophy.
Speaking via the club's official website, Jack said; "It feels really good to be here. I’m really looking forward to getting started and seeing where the season goes. I want to get the club back up, win games and play.
"It was the right time to leave as I want to play league football. It’s a big club and Darrell Clarke is a good manager with young players, so I was eager to get here. I’m a box-to-box midfielder.
"I like to defend, attack, score goals, pass and create. I know it’ll be physical but I want to get used to that as soon as possible. I’m looking forward to the challenge."
