The 19-year-old originally signed professional forms in May 2016 and, after impressing in a reserve team fixture at Hartlepool United, made his debut as a 54th minute substitute in a 2-0 away defeat at Torquay United in the league.
Walton was released by then-boss Gary Mills in May 2017 but was invited back on trial and, after impressing new manager Martin Gray both in training and in reserve team outings against Port Vale and Mansfield Town, was offered a contract to resume his career at Bootham Crescent.