[2] He began playing ice hockey at a young age and also participated in other organized athletics, including baseball and football.

[4] In 2009, Miller moved to Ann Arbor, Michigan, to participate in USA Hockey's two-year National Team Development Program (U.S. NTDP).

[7] Since Miller was drafted by the Rangers from the USHL, he was eligible to join their American Hockey League (AHL) affiliate, the Connecticut Whale, as a teenager.

[1] After the Whale were eliminated, Miller was added to the Rangers roster for the 2012 Stanley Cup playoffs[11] but did not play a single game.

[16] While Rangers assistant general manager Jeff Gorton acknowledged Miller's slow adjustment period, he praised the forward's improvements.

[17] After returning from the 2013 World Junior Championships with a gold medal,[18] Miller became the youngest player named to the 2013 AHL All-Star Game.

[22] Due to the NHL Collective Bargaining Agreement, the Rangers had five games to decide whether they would send Miller down or burn off a year of his contract.

Before he returned to the AHL in April, head coach John Tortorella praised him for his ability to swiftly adapt to playing at the NHL level at a young age.

[35] Unlike the previous season, Miller returned to New York six weeks before training camp began to stay in shape.

[41] Miller was put with Hayes and Hagelin due to an injury to Jesper Fast in early February,[42] and they combined for 27 points through their first 16 games.

[43] When Martin St. Louis was sidelined due to an injury in late March, Miller was promoted the Rangers' second line with Derek Stepan and Kredier.

[44] His game-winning goal on April 2 allowed the Rangers to clinch first place in the Eastern Conference and set a new franchise record for most road wins in a season.

[41] Due to their regular season success, Miller remained on the Rangers' second line to open Game 1 of the 2015 Stanley Cup playoffs against the Pittsburgh Penguins.

After losing Game 1, Vigneault promoted Jesper Fast and demoted Miller to play with Hayes and Carl Hagelin.

[47] Miller assisted on Hayes' second period goal in Game 7 to help the Rangers advance to the Eastern Conference Finals.

[56] While he struggled to score goals[54] his responsible style of play earned him Vigneault's trust and was promoted to the Rangers' second line in November.

[57][58] After recording only one goal through 14 games in November,[54] assistant coach Darryl Williams spoke to Miller about finding consistency.

[52] Due to his play in previous years, Vigneault started Miller on the Rangers' regular penalty-kill unit for the first time to begin the 2016–17 season.

His first point of the playoffs was an asisst on Zuccarello's second goal in Game 6 to help the Rangers qualify for the Eastern Conference second round.

[78][79] However, Vigneault later announced that Miller would start the season in his usual winger position due to the impressive play of other centers at training camp.

[83] In mid-November, Miller was moved from wing to center to replace David Desharnais and gained Grabner and Zuccarello as his wingers.

[89] His efforts helped the Lightning quality for the 2018 Stanley Cup playoffs, where they faced the New Jersey Devils in the Eastern Conference first round.

[91] The Lightning's top line, consisting of Miller, Steven Stamkos, and Nikita Kucherov, struggled with scoring through the first two games of the series.

[97] Despite winning the Presidents' Trophy as the team with the best overall record during the regular season, the Lightning were swept in four games by the Blue Jackets in their first round series.

[99] Miller began the 2019–20 season with a career-high four points, one goal and three assists, in the Canucks home opener against the Los Angeles Kings.

[111] When the NHL returned to play for the 2020 Stanley Cup playoffs, the Canucks moved into the Edmonton bubble along with 11 other Western Conference teams.

[114] He added one goal and seven assists to his points total as the Canucks pushed the Vegas Golden Knights to a final death Game 7.

[115] When the Canucks began experiencing a COVID-19 breakout in April 2021, Miller raised concerns about the health and safety protocols put into place by the NHL.

[120] On April 11, 2023, Miller scored his 200th NHL goal during the Canucks' penultimate game of the season, a 3–2 win over the Anaheim Ducks.

Miller was traded back to the New York Rangers, along with Erik Brännström, in exchange for Filip Chytil, Victor Mancini, and a 2025 first-round pick.[127].