Saginaw Spirit and Detroit Red Wings

On 14 July 2016, the Detroit Red Wings signed Hronek to a three-year, entry-level contract.^[2] Following the completion of the 2016–17 OHL season, Hronek was assigned to the Grand Rapids Griffins on 22 March 2017. In his first season in North America, Hronek recorded 14 goals and 47 assists in 59 games for the Saginaw Spirit. He was tied for fourth among OHL defenceman in scoring with 61 points, and was among the team's leaders with 47 assists (1st), 21 power play points (1st), 14 goals (4th) and 235 shots (2nd) and was named the Spirits' Best Defenceman, and Most Valuable Player.^[3][4]

He made his NHL debut for the Red Wings on 4 October 2018.^[5] On 13 October 2018, Hronek scored his first career NHL goal against Tuukka Rask of the Boston Bruins.^[6] During the 2018–19 season, Hronek recorded five goals and 18 assists in 46 games for the Red Wings. His 23 points led all Red Wings rookies, and ranked fourth in NHL scoring by a rookie defenceman. He finished the season on a four-game point streak, the longest point streak by a Red Wings rookie defenceman since 1991–92, and posted seven total points in his last six games. Following the completion of the Red Wings' season, he was re-assigned to the Griffins.^[7] Hronek was named the 2019 Red Wings Rookie of the Year in voting conducted by Detroit Sports Media.

On 28 August 2020, having returned to his native Czech Republic through the off-season and during the COVID-19 pandemic, Hronek joined former club, Mountfield HK of the ELH on loan until the commencement of the delayed 2020–21 North American season.^[8]

On 3 September 2021, Hronek signed a three-year, $13.2 million contract with the Red Wings.^[9]

Vancouver Canucks

On 1 March 2023, Hronek was traded to the Vancouver Canucks, along with a fourth-round pick in the 2023 NHL Entry Draft in exchange for a first-round and second-round pick in the 2023 NHL Entry Draft. Prior to being traded, Hronek appeared in 60 games with the Red Wings during the 2022–23 season, where he recorded nine goals, 29 assists, four power play goals, 16 power play points, 122 shots and 21:32 average time on ice.^[10][11]

In his first full season with the Canucks, Hronek and his defensive partner Quinn Hughes played important roles in helping the team find early success.^[12] On 15 November, Hronek recorded his first goal with the team and tied the franchise record for longest point streak by a Canuck defenseman. At the time, he had accumulated one goal and 13 assists for 14 points.^[13] By the end of November, Hronek and Hughes led all league defencemen pairs with 59 combined points.^[14] Hronek continued to set new Canucks records as he became the fifth fastest player in Canucks history to record 30 assists since being acquired via a trade.^[15]