Canaco (Vo./Gt.) and Mimori (Dr.), who first connected as bandmates in their high school music club, began performing together after graduating from club activities. Soon after, Kaho (Gt.) and Ayano (Ba.) officially joined, forming the current four-member lineup. In March 2023, following their departure from their previous management agency, the band relaunched under the name Faulieu., embracing a fresh sound and identity. Known for their rich ensemble-driven music, they consistently sell out solo concerts, and as of December 2024, they are affiliated with Amuse Inc.

Their songs are penned by Canaco, with all four members contributing to the composition. The band name Faulieu. is a coined term inspired by the French word milieu, meaning “middle” or “environment.” It blends “Four,” “million,” and “you,” expressing the band’s wish to become a bridge between the four members and the countless “you”s who listen.