Djillali Defali was born in Bordeaux into an artistic family. A self-taught artist, he made his first appearance on the comics front with the one-shot comic book 'La Proie', that was published by Le Cycliste in 1998. He then started the series 'Garous' with scriptwriter Jean-Charles Gaudin, that was published by Soleil between 1999 and 2011. He signed his early work D'Fali, but now he mainly works under the name Defali.
He began a productive association with scriptwriter Éric Corbeyran at Delcourt, with whom he created the fantasy and science fiction series 'Asphodèle' (2003-2005), 'La loi des 12 tables' (2006), 'Uchronie(s) New York' (2008-2010) and 'Septième Sens' (2012).
Defali and Corbeyran were joined by co-scriptwriter Richard Guérineau in the creation of 'Le Syndrome de Hyde' (2007-2010) and by Richard Malka for 'Pulsions' (2008). For publisher Les Deux Royaumes Defali and Corbeyran started the series 'Assassin's Creed'.