Aston-Reese started the 2017–18 season in the minors, but made his NHL debut on February 3, 2018, against the New Jersey Devils.

[9] During Game 3 of Round 2 against the Washington Capitals, Aston-Reese was checked by Tom Wilson, resulting in a broken jaw and a concussion.

[17] On March 21, 2022, Aston-Reese was traded by Pittsburgh, along with Dominik Simon, prospect Calle Clang, and a second round draft choice to the Anaheim Ducks in exchange for Rickard Rakell.

[18] Ahead of the 2022–23 NHL season, Aston-Reese joined the Toronto Maple Leafs for a professional tryout (PTO).

[21] He finished the season with ten goals and 14 points in 77 games and took part in the Maple Leafs' first postseason series win since 2004.

[22] An unrestricted free agent in the offseason, Aston-Reese signed a professional try-out agreement with the Carolina Hurricanes on September 14, 2023.

[22] He opened the 2023–24 season with Detroit's AHL affiliate, the Grand Rapids Griffins, before he was recalled by the Red Wings on October 14, 2023.

[29] However, before playing a game for Vegas, Aston-Reese was claimed off waivers by the Columbus Blue Jackets on October 7, 2024, ahead of the 2024–25 season.

He has two older siblings: a sister, and a brother named William Jr.[31] He attended PS 45 in West Brighton and Morris Intermediate School in Brighton Heights, New York, then enrolled at St. Peter's Prep in Jersey City, where he played his freshman year [32] Aston-Reese was a graphic design major in college and occasionally worked in the Penguins' front office on the design of gameday programs.