Sakai Kenji was born in Osaka (Japan) in 1977. After studying piano and composition in Japan, with Kubo Yoko and Kondo Kei, and also with Maeda Syuichi and Matsumoto Hinoharu at the Kyoto City University of Arts, he moved to Paris in 2002. In Paris he studied composition, electronics, and analysis with Frédéric Durieux, Allain Gaussin, Marco Stroppa, Luis Naon, Claude Ledoux, and Michaël Levinas at the Conservatoire National Supérieur de Musique et de Danse; he later studied further with Michael Jarrell at the Haute École de Musique in Geneva. From 2007 to 2009 he studied at the IRCAM.
His works have been premiered by the Ensemble Intercontemporain, the Ensemble Orchestral Contemporain, and the Contrechamps, Itinéraire, and Sillages ensembles, as well as by the Tokyo Philharmonic Orchestra, the New Japan Philharmonic Orchestra, the Tokyo Sinfonietta, and the Izumi Sinfonietta. They have been performed at a number of festivals, including the Agora Festival (Paris),
the Musica Festival (Strasbourg), the Biennale Musiques en Scène (Lyons), the Archipel Festival (Geneva), and the Suntory Summer Festival (Tokyo), and in prestigious venues such as the Centre Pompidou, the IRCAM, and the Cité de la musique in Paris, the Suntory Hall in Tokyo, and Tokyo Opera City. In May 2011, Nebulous Nix for symphony orchestra was premiered by the Lucerne Symphony Orchestra, conducted by Jonathan Nott, at the KKL Luzern Konzertsaal.
Starting in 2003, he has been awarded numerous grants and prizes, awarded by the Japanese Ministry of Culture, the Rohm Music Foundation, and the Nomura Foundation. He has also won the grand prix at the George Enescu International Competition (2007) and first prize at the Toru Takemitsu Composition Award (2009) and the Art Mentor Foundation Lucerne Award (2010). Helmut Lachenmann, chairman of the Toru Takemitsu Composition Award jury, recognised in this young composer a perfect mastery of composition and a great virtuosity in handling sound and time. His music, marked by clarity and luminosity, develops in a highly personal manner that achieves, unabashedly, a certain form of lightness.