[1] He was a member of the Mega U19 team that won the Junior ABA League for the 2020–21 season, recording 15 points, nine rebounds, and two assists per game.

Mušikić made his senior debut in the ABA League for Mega Basket on 20 January 2022 in a 93–90 win over Partizan NIS, making 10 points, 2 rebounds and an assist in under 20 minutes of playing time.

[3][4] In August 2018, Mušikić was a member of the Serbian under-16 national team that participated at the FIBA U16 European Championship in Novi Sad, Serbia.

[5] In July 2021, Mušikić was a member of the Serbia U19 team at the FIBA Under-19 Basketball World Cup in Latvia.

[7] In July 2022, Mušikić was a member of the Serbian under-20 national team that won a gold medal at the 2022 FIBA U20 European Championship Division B in Tbilisi, Georgia.