Steel first played junior hockey as a youth in his hometown of Sherwood Park, Alberta. While playing for and captaining the Sherwood Park AAA Flyers, Steel was selected with the second overall pick in the 2013 Western Hockey League (WHL) Bantam draft by the Regina Pats. On August 28, 2013, he signed a standard player contract with the Pats. After appearing with the Sherwood Park Crusaders of the Alberta Junior Hockey League (AJHL), Steel completed the 2013–14 season by making his WHL debut with the Regina Pats, featuring in five games.
After the completion of his second full major junior season with Regina in 2015–16, Steel was selected in the same position he was ranked by the NHL Central Scouting, as the final pick of the first round (30th overall) of the 2016 NHL Entry Draft by the Anaheim Ducks. The Ducks previously traded goaltender Frederik Andersen to the Toronto Maple Leafs to obtain the selection used to select Steel. On December 21, 2016, Steel signed a three-year, entry-level contract with Anaheim.
After an impressive 2016–17 season in which he led the WHL in scoring, Steel was awarded the Four Broncos Memorial Trophy as WHL Player of the Year.
In his final season with the Pats, as a member of the 2018 Memorial Cup host team, and despite a 1-2 round robin record, Steel led the hosts to the final, ultimately losing the national championship game 0-3 to Acadie-Bathurst Titan. While not on the championship winning team, and a six-week break between WHL playoff opening round loss to WHL Champion Swift Current Broncos Steel was awarded the Stafford Smythe Memorial Trophy as Tournament MVP, and Ed Chynoweth Trophy as Leading Scorer (2 goals, 11 assists). This followed winning the Gold for Team Canada in Buffalo, New York at the 2018 World Junior Ice Hockey Championships.
Steel joined the Ducks for their 2018–19 season, making his NHL debut on October 3 in a game against the San Jose Sharks. He recorded his first career NHL goal in a 4–2 loss to the Buffalo Sabres on October 21. Steel recorded his first career NHL hat-trick in a 5–4 win over the Vancouver Canucks on March 26, 2019, becoming the youngest player in Ducks history to score a regular season hat-trick.
On August 30, 2022, it was announced that Steel had signed a one-year contract with the Minnesota Wild.[8] In the following 2022–23 season, Steel established new career highs offensively in registering 10 goals, 18 assists for 28 points through 65 regular season games.
As a pending restricted free agent, Steel was not tendered a qualifying offer by the Wild due to salary cap considerations on June 29, 2023. Released as a free agent, Steel was promptly signed at the opening of free agent frenzy to a one-year, $850,000 contract with the Dallas Stars on July 1, 2023
