Bellon joined the Société d'exploitations hôtelières, aériennes, maritimes et terrestres in 1958. He started as a managing assistant, and rose to become CEO of the company.
In 1966, he founded Sodexho SA (renamed Sodexo in 2008). Sodexo supplies a variety of auxiliary services thousands of institutions, including schools, hospitals, retirement centers, corporate and government offices, armed forces, recreational facilities, and correctional institutions. Sodexo is a public traded company on New York and Paris exchanges.
In 1987, he contributed to the creation of the non-profit Association Progrès du Management, which purpose is to focus on the progress of the company through the progress of its Leaders.
Bellon relinquished the group CEO position of Sodexo in 2005, but continued as the chairman of the company until January 2016, when his daughter Sophie Bellon succeeded him as chairman.