Aho was rated amongst the top 20 European forward skaters eligible for the 2015 NHL Entry Draft.[2][3] In the draft, he was selected in the second round, 35th overall, by the Carolina Hurricanes.
On 13 June 2016, Aho signed a three-year, entry-level contract with Carolina.[4] On 13 October 2016, he made his NHL debut—and recorded his first point, an assist—in the opening game of the 2016–17 season.[5] On 12 November 2016, he scored his first goal, which was followed by a second goal in a 5–1 win over the Washington Capitals.[6] On 31 January 2017, Aho scored his first career hat-trick in a game against the Philadelphia Flyers.[7] Consequently, he became the youngest player in Hurricanes/Whalers franchise history to score a hat-trick.[8]
During the 2018–19 season, Aho passed Ron Francis' franchise record for longest season-opening point streak by recording a point in the Hurricanes' first 12 games. As well, it tied an NHL record for recording a point per game from the start of the season.[10] His streak ended on 3 November in a 4–3 overtime loss to the Arizona Coyotes.[11] On 2 January, Aho was selected to participate in the 2019 NHL All-Star Game after leading the team in goals, assists and points through 38 games.[12] On 13 January 2019, Aho recorded his second career hat-trick in a 6–3 win over the Nashville Predators.[13] Aho led the Hurricanes in scoring (five goals, seven assists) during their first trip to the playoffs in 10 years in the 2018–19 season.[14]
On 1 July 2019, Aho signed an offer sheet with the Montreal Canadiens, becoming the first player to sign an offer sheet since Ryan O'Reilly in 2013. The contract included a lucrative bonus structure, including $21.7 million within the first 12 months of the contract.[15][16] On 7 July, the Hurricanes officially matched the offer sheet, re-signing Aho to a five-year, $42.27 million contract.[17]
On 26 July 2023, Hurricanes re-signed forward Sebastian Aho to an eight-year, $78 million contract extension. The deal will begin with the 2024–25 NHL season and will pay Aho an average-annual value (AAV) of $9.75 million through 2031–32.[18]