Born in the family of mother Dunja and father Hrvoje Horvat, one of the worlds best handballplayers of the 20th Century and gold medalist from the 1972 Summer Olympics in Munich, the younger Hrvoje finished primary and secondary school in his native Bjelovar, while in Zagreb he graduated from the University of Zagreb's Faculty of Kinesiology.

[1][2] Horvat started playing handball at ORK Partizan from Bjelovar, where his first coach was Krunoslav "Kuna" Turković.

[1][3] After holding the position of player-coach at RK Dubrava until 2012, Horvat started his indoor handball coaching career in the same club in the same year.

[1][4] In November 2016 Horvat was appointed head coach of RK Nexe Našice, which he led to secure a spot in the final four of the SEHA League in the 2018–19 season and previously won a place in the 2018–19 EHF Cup.

[1][5][6] After Lino Červar became head coach of the Croatia men's national handball team in March 2017, Horvat was appointed his assistant.