[2] As an outfielder for Spruce Creek High School in Port Orange, Florida, Hays developed his arm strength to assist on defensive plays.

[8][9] Hays signed and made his professional debut with the Aberdeen Ironbirds of the Low-A New York-Penn League where he batted .336 with four home runs and 21 RBI in 38 games.

He was supposed to have reported to the Surprise Saguaros on September 11, the first time ever that the Arizona Fall League (AFL) season opened before October.

[20][21] In a 15-inning 11–10 loss to the Toronto Blue Jays at Rogers Centre on September 23, he became the first MLB rookie to have at least five RBIs, a stolen base and an outfield assist in the same game since the RBI became an official stat in 1920.

[22] The Orioles eventually decided not to send him to the Saguaros after he started in 15 of 20 games, batted .313 with a .958 OPS and made several spectacular defensive plays.

On August 11, 2020, Hays hit a two-run inside-the-park home run against the Philadelphia Phillies to break an 8-8 tie.

On January 13, 2023, Hays agreed to a one-year, $3.2 million contract with the Orioles, avoiding salary arbitration.

He was named the starting center fielder for the game, replacing Mike Trout, who withdrew due to injury.

On July 26, 2024, Hays was traded to the Philadelphia Phillies in exchange for Seranthony Domínguez and Cristian Pache.