Joris Lacoste has been writing for theatre and radio since 1996 and has been directing his own performances and shows since 2003: 9 lyriques pour actrice et caisse claire in 2005, Purgatoire in 2007, and Le vrai spectacle in 2011. In 2004, he founded the collective research project W. He was an associate author at the Théâtre de la Colline in 2006-2007. From 2007 to 2009, he was co-director of the Laboratoires d'Aubervilliers.
In 2007, he founded the collective Encyclopédie de la parole, within the framework of which he created the shows Parlement (2009), Suite n°1 (2013), Suite n°2 (2015), blablabla (2017), Suite n°3 (2017), Jukebox (2019) and Suite n°4 (2020). The performances of the Encyclopédie de la parole have been shown worldwide and were given a Portrait at the Festival d'Automne à Paris in 2020.
In 2018, he created the piece Noyau ni fixe with 9 young performers from the Talents Adami program. In 2023, in Ghent, he created the very first stage version of Luciano Berio's A-Ronne with the Ensemble HYOID conducted by Filip Rathé. Joris Lacoste has also created numerous performances and taken part in several exhibitions in museums and art centers. He has also translated four Shakespeare plays for directors Gwénaël Morin and Marie Lamachère.