He won a bronze medal in the K-2 500 m event at the 2009 ICF Canoe Sprint World Championships in Dartmouth. At the 2012 Summer Olympics, he competed in the Men's K-4 1000 metres, finishing in 4th place with the team in the final. Gross teamed up with Max Rendschmidt to win the K-2 1000m at the 2013 World Championships and the 2013 European Championships. They defended their European title in 2014. In June 2015, he competed in the inaugural European Games, for Germany in canoe sprint, more specifically, Men's K-2 1000m with Max Rendschmidt. He earned a silver medal. The team also won the K2 500 m at the 2015 European Championships. At the 2015 World Championships, Gross and Rendschmidt won the men's K-2 1000m. Gross marked the occasion by proposing to his girlfriend.