Gassama was born in Mali. He travelled to Europe via Burkina Faso, Niger and Libya, where he was arrested and beaten. He crossed the Mediterranean and obtained papers to stay legally in Italy, but travelled to France in September 2017 to join his elder brother. News reports emphasized the similarity between Gassama and Lassana Bathily, a Muslim immigrant from Mali who was hailed as a hero in France and offered citizenship for his bravery in the Hypercacher kosher supermarket siege of 2015. On 24 June 2018 Gassama received the BET Humanitarian Award in Los Angeles.