Born in Bruges (1983), Daan Janssens studied at the local music school, where he got his first composition lessons with Octaaf Van Geert. He studied composition at the Ghent Conservatory with Frank Nuyts, Godfried-Willem Raes and Filip Rathé. He visited several international composition seminars and master classes. Since October 2016, he teaches composition and orchestration at the Royal Conservatory Ghent.

Daan Janssens collaborated with both Belgian and international ensembles and soloist, such as SPECTRA, Ensemble Intercontemporain, Aton & Armide, Ensemble Musiques Nouvelles, Gulbenkian Orchestra Lisbon, I SOLISTI, Thomas E. Bauer... during such festivals as the TRANSIT festival, Ars Musica, Festival Musica Strasbourg, De Singel, Concertgebouw Brugge, Operadagen Rotterdam, De Munt/La Monnaie.

Since 2008, Janssens collaborates intensively with LOD, a Ghent-based music theatre production house. In 2012, he presented his first opera, Les Aveugles, after Maurice Maeterlinck, in collaboration with Patrick Corillon. In April 2017, his second opera was premiered, Menuet, after a novel by Louis Paul Boon, in a stage direction of Fabrice Murgia. Currently, he is working on his third opera, Brodeck, after a novel by Philippe Claudel, again in collaboration with Fabrice Murgia.