After completing his minor career with the Marlboros, Hughes was drafted eighth overall by the Mississauga Steelheads in the Ontario Hockey League, despite his commitment to the U.S. National Team Development Program (USNTDP).

[4] During the 2018–19 season, Hughes broke the NTDP all-time points record that was previously held by Clayton Keller.

[9] Two days later, he recorded his first career NHL goal in a 1–0 win over the Vancouver Canucks and his older brother, Quinn.

[15] The 2022–23 season saw Hughes hitting career highs in goals (43), assists (56) and points (99), while leading the Devils to third in the NHL and a franchise-high 52 wins.

[19] Hughes was also nominated for the Lady Byng Memorial Trophy, an award granted to the player exhibiting the best "sportsmanship and gentlemanly conduct combined with a high standard of playing ability".

[21] Hughes went on to have three goals and five points in the series, with the Devils eliminating the Rangers in seven games and advancing to the Second Round for the first time since the 2011–12 season.

[24] On November 3, 2023, during the Devils' 4–1 loss to the St. Louis Blues, Hughes fell into the boards at high speed and left the game with a shoulder injury.

[29][30] Hughes sustained an upper-body injury for the second time that season on January 5, when he fell awkwardly late in a 4–2 victory over the Chicago Blackhawks, and was unable to participate in the All-Star Game.

[37] Hughes missed three games of the tournament with an undisclosed injury but returned to the lineup in time to help Team USA beat the Czech Republic.

He later competed at the 2019 World U18 Championship, where he broke Alexander Ovechkin's goals scored record as Team USA won a bronze medal.

[39] On May 1, 2019, Hughes was named to the senior United States roster to compete at the 2019 World Championship, again alongside Quinn.

[50] She also played for the United States women's national ice hockey team, and won a silver medal at the 1992 World Championship.