On October 6, 2020, Lapierre was selected by the
Washington Capitals with the 22nd overall pick in the
2020 NHL entry draft. He was signed to a three-year, entry-level contract with the Capitals on October 27, 2020. Following his third season of major junior hockey with the
Chicoutimi Saguenéens of the
Quebec Major Junior Hockey League (QMJHL), Lapierre was traded to
Acadie–Bathurst Titan in exchange for two junior players and four draft selections on June 23, 2021. 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. ==Career statistics==