Marin began his career in the academy of Italian side Lazio, where head coach Simone Inzaghi promoted him from under-17 level to Primavera, where he played alongside players older than him due to his high potential.[2] Due to this experience, he was scouted and signed by English Premier League side Manchester City in 2012.[2] Following the move, Lazio complained that Marin had been tapped up, with his agent, Dario Canovi, stating that the club should have asked themselves why Marin chose to leave.[3][4] His spell with Manchester City lasted for one season before a return to Italy with Juventus.[5]
In December 2020, after over a year without a club, he signed for Serie D side Fossano.[6] He renewed his contract ahead of the 2022–23 season.[7]
International career
Having not received a call-up to the Romanian national youth teams, Marin stated that he was "still Italian" in an August 2012 interview with Sport.ro.[8] The following year, he was called up to represent Romania at under-19 level, and went on to make five appearances.[1]