Cimermancic began playing youth soccer for seven years with Kitchener SC, before joining the Toronto FC Academy in February 2015.[1] In 2019, he was part of the TFC U15 team that were the U.S. Soccer Development Academy conference champions after posting an undefeated regular season and reached the 2019 Generation Adidas Cup finals and becoming the first Canadian team to win the USSDA National Championship.[1]
In 2022, he played with Toronto FC II in MLS Next Pro as an academy callup, making his debut on May 8, 2022 against New York City FC II.[1] In March 2023, he signed a full professional contract with the team.[1] On March 24, 2023, he joined the first team on a short-term four day loan ahead of the team's match against the San Jose Earthquakes.[3] He signed two additional short-term loans that season.[4][5] The following season, he signed another four short-term loans in June and July.[6][7][8][9] Toronto FC II exercised Cimermancic's contract option following the 2024 season.[10]