[2] During the tournament, he scored four goals and two assists in their 11–3 quarterfinals win and finished their state championship run with 11 total points.

[5] Following high school, Koepke joined the Sioux City Musketeers of the United States Hockey League (USHL) for two seasons and served as an assistant captain for one.

[9] Koepke joined the Minnesota Duluth Bulldogs men's ice hockey team as a rookie for their 2018–19 NCAA season.

During the season, he often skated on the left wing on a line with Parker Mackay and Justin Richards who helped him record 19 points.

[13] He helped the Bulldogs return to the NCAA Frozen Four, recording one goal, as the team lost in the semi finals to the eventual champions the University of Massachusetts Minutemen.

[20] Following four seasons within the Lightning organization, Koepke left as a free agent and was signed to a one-year, two-way contract with the Boston Bruins on July 1, 2024.