Mihăilă began his professional career at Universitatea Craiova in 2017, appearing in over 60 Liga I matches before signing with Italian team Parma for €8.5 million three years later.
[6] He amassed 32 matches across all competitions in the 2018–19 campaign, and in December 2019 manager Victor Pițurcă confirmed that Craiova rejected a €5 million bid for him from fellow league team FCSB.
[7] During his third season in Oltenia, Mihăilă totalled nine goals and came close to claiming the national championship; his side however lost the final fixture 1–3 to eventual champions CFR Cluj on 3 August 2020.
[19] Mihăilă struggled with recurring injuries before regaining his fitness in the 2023–24 season, aiding with 6 goals from 35 appearances in all competitions as Parma won its first-ever Serie B title and reached the top division after a three-year pause.
Mihăilă attracted significant media attention after contributing to Romania national under-21 team's victory in a UEFA Euro 2021 qualifier against Finland on 14 November 2019, as he scored a hat-trick and provoked an own goal.
[20] In March 2021, Mihăilă was called up for the first time to the Romania squad by head coach Mirel Rădoi for the 2022 FIFA World Cup qualifiers against North Macedonia, Germany, and Armenia.