Gros played in France for Le Havre and in his native Réunion for JS Saint-Pierroise before signing for Scottish club Kilmarnock in September 2010. After making a substitute appearance, he scored on his debut for the club in March 2011. Gros signed a new three-year contract with the club in August 2013. In March 2014, following a lack of games, Gros announced he was considering his future at the club.
In June 2014 Gros went on trial with English club Oldham Athletic. On 21 July 2014, Gros signed a one-month contract with the club. Oldham manager Lee Johnson told Gros to prove his fitness in order to earn a longer contract with the club. Gros was released by the club on 21 August 2014.