On 28 December 2009, he won the first ever French edition of The X Factor broadcast on W9 Network in France beating the 17-year-old Marie in the finals.
In April 2010, Agius also engaged in a tour of French and Belgian venues alongside Season 1 finalists Cyrielle, Gauthier Dymon and Guillaume.
[16][17] "Ma Chance" did not meet the success the X factor winner hoped for, and the album sales were disappointing.
[19] Agius shifted gear and started appearing in musical comedies including the 2011 production Dracula, l'amour plus fort que la mort (Globe de Cristal Award 2012) by Kamel Ouali where Agius played the double roles of the sorcerer and the angel.
In 2016, Sébastien took part to the 5th season of The Voice : France with Roxane Le Texier under the name of Louyena.