His humanitarian work began with the creation in 2004 of the charity NGO Solidarity for Kosovo, which was founded in response to the anti-Serb unrest that afflicted Kosovo and Metohija on March 17 and 18, 2004. He came to Serbia for the first time in 2005 with his brother Bertrand and two friends bringing the humanitarian aid gathered in France. Gouillon's brothers’ small student organization quickly grew into one of the largest charities operating in the Balkans.