His agency, Office Augusta, announced his passing in an official statement on May 13, expressing heartfelt gratitude for the support and kindness shown to him throughout his lifetime. The statement added that up until just before he died, Oono had been living his life normally until he passed away peacefully while sleeping. Private funeral and memorial services were held with close family per his relatives’ wishes. A public gathering will be held at a later date.
The statement also confirmed that the concert on May 30 at Billboard Live Tokyo will continue as planned because Oono had already finished preparing for the show.
Oono began his recording career as a versatile jazz pianist and composer in 1966. During the mid-1970s, he took a break from playing the piano in order to concentrate more on composition. This transition turned out to be crucial, as he became one of the key figures in anime music composition, particularly for his works in the Lupin III franchise. His work on Lupin III: Part II and the movie Lupin III: Cagliostro no Shiro (Lupin III: The Castle of Cagliostro) gained him worldwide recognition.
Beyond Lupin III series, Oono composed scores for many notable anime titles, including Space Cobra (Space Adventure Cobra), Gakuen Senki Muryou (Shingu: Secret of the Stellar Wars), Time Slip Ichimannen (Prime Rose), Kaitei Choutokkyuu: Marine Express (Undersea Super Train: Marine Express), and 100-man-nen Chikyuu no Tabi: Bander Book (One-Million Year Trip: Bander Book). His extensive career lasted nearly six decades, producing more than 50 film and television scores.
Source: Sponichi Annex, Oricon Music