On October 6, 2020, Lapierre was selected by the Washington Capitals with the 22nd overall pick in the 2020 NHL entry draft.[2] He was signed to a three-year, entry-level contract with the Capitals on October 27, 2020.[3]
Lapierre made his NHL debut for the Capitals on October 13, 2021, at home against the New York Rangers. He scored his first NHL goal in the second period of that game on an assist from T. J. Oshie. In 2023, and 2024, Lapierre won the Calder Cup with the Hershey Bears, the farm team of the Washington Capitals. He was named the MVP of the 2024 Calder Cup playoffs. [5]