Miller reached the peak of his NHL career to conclude his first season with the Carolina Hurricanes in 2025-26, his Stanley Cup Playoff-career high nine points (all assists) in 19 games breaking his previous best of seven (two goals, five assists) set with the New York Rangers in 2022 playing a role in the Hurricanes winning the Stanley Cup with a six-game victory against the Vegas Golden Knights. At the time Miller lifted the Cup, he was 19-1 (8-1 with Carolina) in the playoffs when getting at least one point.

Miller had 37 points (eight goals, 29 assists) after he was traded to the Hurricanes by the Rangers on July 1, 2025, subsequently signing an eight-year, $60 million contract. New York's first-round pick (No. 22) in the 2018 NHL Draft was first among Rangers defensemen and 10th in the NHL at his position in takeaways (47) and second among New York defensemen in hits (107) and blocked shots (110). He had 132 points (36 goals, 96 assists) for the Rangers prior to joining the Hurricanes and made the 2021 NHL All-Rookie team with 12 points (five goals, seven assists) and a plus-7 rating in 53 games of a 56-game season.

Prior to turning pro, Miller played two seasons at the University of Wisconsin (40 points; 12 goals, 28 assists) in 62 games and earned B1G All-Rookie Team honors in 2018-19 with 22 points (five goals, 17 assists) as a freshman year. He also played two seasons with the United States National Team Development Program and in a number of international competitions, winning silver at the 2018 IIHF World under-18 Championship and the 2019 IIHF World under-20 Championship.