Hintz signed an eight-year, $67.6 million contract with the Dallas Stars on Nov. 29, 2022, preventing him from becoming a restricted free agent. He set new NHL career highs of 38 assists and 75 points in 2022-23, while tying his best of 37 goals. Hintz then started the 2023 Stanley Cup Playoffs with 11 points in five games to pass Mike Modano (10 points, 2003 Western Conference Quarterfinal), Sergei Zubov (10 points, 2003 Western Conference Quarterfinal) and Jamie Benn (10 points, 2016 Western Conference First Round) for most in a playoff series since the Stars relocated to Dallas for the 1993-94 season.

Hintz helped Team Finland win bronze at the Olympic Winter Games Milano Cortina 2026. His 24 points (10 goals, 14 assists) in the 2023 playoffs are tied with Brett Hull (2000) for the second-most in team history since the Stars relocated to Dallas in 1993 behind Miro Heiskanen's 26 in 2020.

After Hintz had surgery to repair a tendon issue in his groin area in May 2021, he responded by finishing third on the Stars in points (72) while scoring 37 goals and 35 assists while averaging 18:02 of ice time in 80 games. He also had 13 points (two goals, 11 assists) in 25 playoff games to help the Stars advance to the Stanley Cup Final in 2020, a six-game loss to the Tampa Bay Lightning.

Hintz impressed in 2017-18, his first season in North America, but the Stars held off on promoting him from Texas of the American Hockey League. The forward used that full season in the minors to make important strides on the way to becoming an NHL regular.

Hintz scored 35 points (20 goals, 15 assists) in 70 games that season for Texas, then had 14 points (four goals, eight assists) in 22 playoff games to help Texas reach the Calder Cup Finals, where it lost to Toronto in seven games.

That performance led to Hintz making Dallas' 2018-19 opening night roster. After being sent down later in October, he scored his first NHL goal Nov. 18, 2018, at the New York Islanders one day after being recalled. He played 58 games as a rookie in 2018-19.

Among Stars forwards, he tied Devin Shore for third with three game-winning goals and was fourth with three power-play goals. Hintz then scored five goals in 13 playoff games, tying forward Alexander Radulov for the team lead. Hintz followed that by scoring 19 goals and 33 points in 60 games in 2019-20 and 13 points (two goals, 11 assists) in 25 postseason games, helping the Stars reach the Cup Final for the first time since 2000.

The Stars selected Hintz in the second round (No. 49) of the 2015 NHL Draft. He signed a three-year, entry-level contract with Dallas on May 4, 2017, after scoring 30 points (11 goals, 19 assists) in 44 games in 2016-17 for HIFK in Liiga, the top professional league in his native Finland.