[2] As the team qualified for the 2017 OHL playoffs, he led all Greyhounds skaters in both goals and points through 11 games, and was then signed to a three-year, entry-level contract by the Lightning on April 23.
During their series against the Owen Sound Attack, Katchouk scored a hat trick to help lift the Greyhounds to a Game 7 win and qualify for the OHL's Western Conference final.
[16] Following his major junior career, Katchouk was assigned to the Lightning's American Hockey League (AHL) affiliate, the Syracuse Crunch.
[18] Katchouk returned to the AHL for the 2020–21 season, appearing in 29 games, scoring 11 goals and 34 points, leading the team in assists and plus/minus.
[19] After attending the Lightning's training camp and participating in pre-season games, Katchouk was named to their opening night roster.
[20] On October 16, Katchouk made his NHL debut in a 7–6 Lightning overtime victory against the Detroit Red Wings at Little Caesars Arena.
[23] On December 5, Katchouk recorded his first career NHL goal against Carter Hart in a 7–1 Lightning win over the Philadelphia Flyers.
[29] Katchouk suffered a left ankle sprain in a 2022 pre-season game versus the Detroit Red Wings that caused him to miss the first month of the 2022–23 season.
[34] After appearing in six games with Rockford, scoring three goals and five points, Katchouk was recalled by Chicago after Raddysh was placed on injured reserve on December 30, 2023.
[39] Katchouk scored his first goal and registered his first multi-point game with the Senators in a 6–2 win over the Buffalo Sabres on March 27.
[41] As a free agent, Katchouk went un-signed in the 2024 offseason before he accepted an invitation to attend the Anaheim Ducks training camp for the 2024–25 season on a professional tryout (PTO) on September 12, 2024.
[44] Katchouk was a member of Team Canada at 2016 Under-18 Championships in Grand Forks, North Dakota, United States.