ACS Poli Timișoara head coach Dan Alexa handed Marin his senior debut on 23 May 2015, aged 16, in a 5–0 thrashing of Unirea Tărlungeni in the Liga II championship.
[11] Marin registered his debut for Romania under-21 on 10 October 2019, in a 3–0 win over Ukraine counting for the 2021 UEFA European Championship qualifiers; he received a red card just one minute after entering the field.
[12] Manager Adrian Mutu called up Marin for the final tournament hosted by Hungary and Slovenia,[13] and he captained the side in the first two group games before missing the last one through a suspension.
Marin made his full debut for Romania on 5 September 2021, coming on as a 63rd-minute substitute for Darius Olaru in a 2–0 World Cup qualifier defeat of Liechtenstein.
[19] He started in all four matches of the tournament, forming a midfield partnership with Răzvan Marin and Nicolae Stanciu, as the nation won its group but was eliminated by the Netherlands in the round of 16.