Shibasaki has two units: Koh+ (with Masaharu Fukuyama) and Galaxias! (with Deco*27 and TeddyLoid). Shibasaki made her debut in the music industry in 2002 with her first single, "Trust My Feelings", but she became recognized for her second single, "Tsuki no Shizuku", which was used for the movie Yomigaeri.
Although unable to compose (mainstream) music on her own, Kō Shibasaki writes the lyrics for most of her songs. Many of her singles have become theme songs for various films, dramas, and commercials. Her single "Lover Soul" was the ending theme song for the live action dramaOtomen.
Shibasaki debuted in 2000 when she portrayed the cold, deadly, and promiscuous Mitsuko Souma in the cult classic Battle Royale. Her acting career took off with this film and also raised her international profile not only in Japan, but all over East Asia. Shibasaki also won critical acclaim for her role as Tsubaki Sakurai in the 2001 film Go, which earned her several awards, including the Best Supporting Actress Award of Japanese Academy, the Hōchi Movie Award, the Kinema Junpō Award. Since her debut in 2000, Shibasaki has worked in numerous television shows, movies and commercials. Her stage name is taken from the main character of Junko Kawakami's manga Golden Delicious Apple Sherbet.
In March 2011, it was announced that Shibasaki would make her "Hollywood debut" in a Keanu Reeves-led adaptation of the famous Chushingura story. A story of samurai loyalty and revenge and titled 47 Ronin, it is billed as the first ever English-language adaptation of the legend based on historical events in the early 18th century.