Petar Musa was born in Zagreb and began his senior career with NK Zagreb before moving to the Czech Republic, where he played for Slavia Prague with loan spells at Viktoria Žižkov and Slovan Liberec, finishing as the league's top scorer in 2019/20. After a loan at Union Berlin and a season at Boavista, he signed for Benfica in May 2022.

A tall centre-forward who offered a physical presence and an aerial threat, he was used largely from the bench in Lisbon.

In 2023/24 he scored in the Supertaça Cândido de Oliveira win over Porto in August, but was sent off in the opening league defeat at Boavista and remained a squad option thereafter. On 1 February 2024 he joined FC Dallas for a club-record fee.

He won the Primeira Liga in 2022/23 and has been capped by Croatia.