Amateur Gersich attended
Holy Family Catholic High in Minnesota before moving to the
United States Hockey League with the
Omaha Lancers and the
U.S. National Team Development Program (NTDP). As an eighth grader, Gersich tallied 16 goals and 23 assists through the 2010–11
Minnesota State High School League regular season. Due to the hockey teams' success, Holy Family Catholic opted to move from Class 1A to 2A for the 2011–12 season. He was also selected to represent Team USA at the
inaugural Winter Youth Olympic Games. As a freshman at Holy Family Catholic, Gersich accumulated 30 goals and 30 assists and was subsequently offered an opportunity to play with the
USA Hockey National Team Development Program for the 2012–13 season. However, he turned down the offer and was drafted first overall by the
Omaha Lancers in the 2012
United States Hockey League Futures Draft. During the summer following the draft, Gersich again represented Team USA at the international level to help them win gold at the U-17 Five Nations tournament. Although he injured his shoulder during the tournament, Gersich skated with Team Southwest in the Upper Midwest High School Elite Hockey League but sat out the final several weeks of the season. Gersich returned to Holy Family Catholic for his sophomore year in the 2012–13 season. By December 2012, he shared the scoring lead with six goals and nine assists for 15 points through seven games. As such, he was recruited by numerous Division 1 programs before committing to a collegiate career with the
University of North Dakota of the
National Collegiate Hockey Conference (NCHC). He finished the season with 28 assists and 34 assists for 62 points through 24 games. Following this, he was also invited to participate in the second annual CCM/USA Hockey All-American Prospects Game. Upon joining the NTDP, Gersich continued to flourish and quickly accumulated 14 goals and 27 points by March 2014. He credited his easy transition to the coaching of Danton Cole and John Gruden.
Collegiate Following his first full season with the Lancers, Gersich began his collegiate career with the
North Dakota Fighting Hawks men's ice hockey team while majoring in communication. As his freshman season continued, Gersich ranked third among UND freshmen with nine goals through 37 games as he helped lead the team the national championship. He immediately joined the Capitals roster for the remainder of the season and made his professional debut, going scoreless, in a 3–2 overtime victory over the
New York Rangers on March 28, 2018. Despite going scoreless in his debut, Gersich earned his first NHL point in his third NHL game on April 7, in a 5–3 win over the
New Jersey Devils. After
Tom Wilson was suspended in the second round of the
2018 Stanley Cup playoffs, Gersich played in Games 4 and 5 against the
Pittsburgh Penguins en route to the Capitals winning the
Stanley Cup. Following their Stanley Cup run, the Capitals re-signed Gersich to a one-year, two-way contract with a
cap hit of $700,000. Out of contract with the Capitals following the season, Gersich opted to remain within the organization in signing a one-year AHL contract with the Hershey Bears on August 25, 2022. In the
2022–23 season, Gersich added 9 goals and 23 points through 53 regular season games. He featured in 6 postseason games with the Bears to help the club claim their 12th
Calder Cup Championship. Following five seasons with the Bears, Gersich signed his first contract abroad in agreeing to a one-year deal with Swedish second tier club,
Västerås IK of the
HockeyAllsvenskan, on June 23, 2023. ==Career statistics==