Youssef developed an interest in jazz at an early age and clandestinely listened to it during his education at a Qur'anic school. He later left Tunisia to start a jazz career and has lived in Europe since 1990, usually in Paris or Vienna. He also works in avant garde and world music where he has been nominated for awards. He has released six albums of his own and created notable work with Sardinian trumpeter Paolo Fresu and the Norwegian guitarist Eivind Aarset. He has an affinity for the music of India and Nordic music. He was a guest artist on the Norwegian jazz artist Bugge Wesseltoft's album FiLM iNG. Youssef has also performed with Uri Caine, Tigran Hamasyan, Jon Hassell, Markus Stockhausen, Nguyên Lê, Omar Sosa and Hüsnü Şenlendirici.

In 2001, he recorded Electric Sufi with the ex-Sugar Hill Gang and Tackhead rhythm section of Will Calhoun and Doug Wimbish.

In 2015, Youssef opened the Sligo Jazz project with a quartet act at the Hawk’s Well Theatre at Connacht, Ireland.