2010-11: Shane Gersich played for Holy Family Catholic HS in Victoria, MN as an eighth-grader. In 25 games he scored 16 goals with 25 assists, including 2 assists in two sectional playoff games, and was +19 with 20 penalty minutes. Holy Family defeated St. Louis Park before falling, 3-1, to Delano in the Section 2A quarterfinals. Gersich participated in USA Hockey's Select 15 Player Development Camp in July.
2011-12: Gersich was the second-leading scorer for Holy Family Catholic as the Fire moved up from the A to AA (large school) division in Minnesota. In 21 games he scored 30 goals with 30 assists and had 21 penalty minutes. Holy Family lost to eventual state champion Benilde-St. Margaret's, 7-0, in its first-ever Section 6AA playoff game. Gersich played for the USA's U16 team in the 2012 Youth Olympic Games, scoring 3 goals with 1 assists and finishing -4 with 6 penalty minutes in six games. The USA lost 7-5 to Canada in the bronze medal game. Gersich was invited to USA Hockey's Select 16 Development Camp and was chosen for the U17 team that competed at the 2012 Five Nations Tournament in August. Gersich was selected by Omaha with the first overall pick in the 2012 USHL Futures Draft.
2012-13: Gersich made his USHL debut, appearing in six games with the Omaha Lancers in March following the high school season. He began the year with the USA's U17 team in August, scoring 1 goal with 5 assists in two games as the USA finished first in the Five Nations Tournament in Chomutov. Gersich played for Team Northwest in the Upper Midwest Elite High School League in the fall before his sophomore season at Holy Family Catholic. He scored 1 goal and was -4 with 19 penalty minutes with the Lancers. In seven games for Team Southwest he scored 5 goals with 3 assists. Gersich was the leading scorer for Holy Family, the top team in Wright County, scoring 28 goals with 34 assists and 65 penalty minutes in 25 games. The Fire lost to Eden Prairie, 7-1, in the Section 6AA playoffs. Gersich attended USA Hockey's Select 17 Development Camp and was invited to join the National Team Development Program in Ann Arbor Michigan. In December he committed to playing college hockey at North Dakota in 2015-16.
2013-14: Gersich joined the NDTP's U18 team — foregoing his final two years of high school hockey in Minnesota. In 47 regular season games he scored 14 goals with 13 assists and had 16 penalty minutes. He scored 6 of his 14 goals on the power play. Gersich played in the 2013 USA Hockey/CCCM All-American Prospects game and was ranked 81st amongst North American skaters in Central Scouting's mid-term rankings prior to the 2014 NHL Draft.