He received his PhD in social history from the Universidade Estadual de Campinas (Unicamp). He was a visiting professor at Duke University (2004) and Princeton University (2006/7). A historian of Brazilian labour and working-class culture in São Paulo after World War II, Fontes has studied internal migration from the Northeast to São Paulo, the links between rural and urban workers, the role of place and communities in working-class formation, and the cultural aspects of popular organisation and politics. In 2011, his book Um Nordesteem São Paulo. Trabalhadores Migrantes em São Miguel Paulista, 1945—1966 won the first Thomas Skidmore Prize, sponsored by the National Archive and the Brazilian Studies Association. As a result, the book is due to be published in English by Duke University Press in 2014.