Laczynski came into play during the 2020-2021 season. Laczynski played 14 games in the shortened season and posted 6 goals with 4 assists. He earned call-ups to the NHL and played in 5 games with no points posted. His season came to a quick end when he needed season-ending surgery to his hip.

The 2021-2022 season started, and again, Laczynski missed the start of the season due to needing surgery on his other hip. This time, Laczynski came back to play in February 2022. During the span of his return, he played in 28 games posting seven goal with 10 assists. He earned a call up to the Flyers for one game during this season.

Laczynski vyed for a spot on the 2022-2023 roster for the Flyers and earned it. He was sent down to the AHL for two games and posted one goal and two assists during those two games, which were on the road. Laczynski played in 32 games for the Flyers during the course of the season, in which he posted two goals and two assists.

During the course of the 2023-2024 season, Laczynski was a pivotal member of the Lehigh Valley roster. He dressed for 49 games and tallied 17 goals with 27 assists. He played in six post season games and posted four goals.

Laczynski was a depth forward in the Flyers organization, but injuries hindered his chances at a steady NHL roster spot. Lacyznski will add the depth that the Golden Knights need in the organization.