York was born and raised in Anaheim, California. While there, he played alongside Jackson Niedermayer, the son of Scott Niedermayer, who coached his youth hockey team. His father, Jeff, installed a roller skating rink surface in the backyard which York would skate on every day after school. It was through roller skating that York developed an affinity for hockey. After two defencemen on his youth team were injured, he was placed on defence and enjoyed the position. York played squirt and peewee hockey within the Anaheim Jr. Ducks minor program under coaching of Craig Johnson and Scott Niedermayer. Once he turned 14, York enrolled in Shattuck-St. Mary's, a Minnesota prep academy, where he totaled more than 100 points in two seasons. Afterwards, York was invited to the USA Hockey National Team Development Program in the USHL. While playing for the USA Hockey National Team Development Program U-18 team in the 2018–19 USHL season, York set a new single season record for points for a defenseman. On January 15, 2019, York set a new franchise record for most points in one game with seven. This earned him USHL's Defenseman of the Week Honors. York was initially committed to play for Boston College, but rescinded his commitment when coach Greg Brown left to join the New York Rangers. He eventually committed to play for the University of Michigan Wolverines.
Collegiate
He was drafted 14th overall by the Philadelphia Flyers in the first round of the 2019 NHL Entry Draft. He enrolled in the University of Michigan for the 2019–20 season and recorded his first collegiate goal in a 2–1 loss to Ohio State on November 2, 2019.
International play
On April 4, 2018, York was selected to compete for Team USA at the 2018 IIHF World U18 Championships. He recorded 6 points and was named to the Media All-Star Team as Team USA won a silver medal. York was again selected to compete for Team USA at the 2019 IIHF World U18 Championships on April 11, 2019. During the tournament, he set a new scoring record for defenseman in U18 Men's World Championship history. His 17 points collected during the 2018 and 19 series helped earn him the honor of Three Best Players of the tournament for Team USA, U.S. Player of the Game, and a bronze medal.
