Hosokawa studied with Yun Isang at the Berlin University of the Arts. Since 1998, Hosokawa has served as Composer-in-Residence at the Tokyo Symphony Orchestra. In 2004, Hosokawa became a guest professor at Tokyo College of Music. In 2001, Hosokawa became a member of Academy of Arts, Berlin.
Invited by Walter Fink, he was the 18th composer featured in the annual Komponistenporträt of the Rheingau Musik Festival in 2008, in chamber music, played by the Arditti Quartet and Mayumi Miyata (Shō), and the oratorio Voiceless Voice in Hiroshima, performed by the WDR Symphony Orchestra and Choir, Cologne conducted by Rupert Huber.
Awards and honors
Hosokawa has received the following awards and honors.
- First Prize in the Composition Competition which marked the 100th Anniversary of the Berliner Philharmoniker (1982)
- Rheingau Musikpreis (1998)
- Duisburger Musikpreis (1998)
- musica viva-Preis der ARD und BMW AG (2001)
- the 39th Suntory Music Award (2007)
|Premiere||Title||Description||Libretto and source|
|1998041919 Apr 1998, Gasteig/ Munich Biennale||Vision of Lear||Opera in 2 acts, 105'||Tadashi Suzuki, after his stage play The Tale of Lear|
|2004070808 Jul 2004, Théâtre du Jeu de Paume/ Festival d'Aix-en-Provence||Hanjo||Opera in 1 act, 80'||the composer, after the English translation by Donald Keene of the modern Noh play by Yukio Mishima|
|201105033 May 2011, La Monnaie, Bruxelles||Matsukaze||Opera in one act, 80'||Hannah Dübgen, after the Noh play Matsukaze by Zeami|
- Voiceless Voice in Hiroshima for soloists, narrators, chorus, tape (ad lib.) and orchestra (1989/2001) after Matsuo Bashō, Paul Celan and Genbaku no Ko
- Preludio (1982)
- In die Tiefe der Zeit (Into the Depths of Time)
- Ferne Landschaft I (a work commissioned by Kyoto city. 1987, Kenichiro Kobayashi & Kyoto Symphony Orchestra.)
- Ferne Landschaft II (a work commissioned by the Gunma Symphony Orchestra. 1996, Ken Takaseki & Gunma Symphony Orchestra.)
- Ferne Landschaft III-seascapes of Fukuyama (a work commissioned by Fukuyama city. 1996, Naohiro Totsuka & Hiroshima Symphony Orchestra.)
Orchestra, Koizumi, Kazuhiro conductor.
- Circulating Ocean (2005)
- danses imaginaires (2007)
- Woven Dreams (2009–10)
- Meditation (2011–12) to the victims of Tsunami (3.11)
- Flute Concerto Per Sonare (1988)
- Cello concerto (1997)
- Voyage II for bassoon and ensemble (1997)
- Horn Concerto Moment of Blossoming (2010)
- Landscape V for shō and string quartet (1993)
- Silent Flowers for string quartet (1998)
- Deep Silence (2002), duets for shō (bamboo mouth organ), and accordion in the Gagaku style, including:
- Cloudscapes - Moon Night
- Wie ein Atmen im Lichte after a drawing of Rudolf Steiner
- Sen V
- Blossoming for string quartet (2007)
- Lied II (リート Ⅱ) for viola and piano (2008)
- Für Walter for soprano saxophone and piano, percussion ad libitum (2010), dedicated to Walter Fink for his 80th birthday
- Spell (呪文) for violin solo (2010)
- Lullaby of Itsuki: from Japanese Folk Songs (五木の子守歌 −日本民謡より−) for violin and piano (2011)
- Threnody: To the Victims of the Tōhoku Earthquake 3.11 (哀歌 −東日本大震災の犠牲者に捧げる−) for viola solo (2011)
- "Renka I" for soprano and guitar (1986)
- "Three love songs" for voice and alto saxophone (2005)
- "Drei Engel-Lieder" for soprano and harp (2014)
- "Ave Maria for 16-part mixed choir a cappella (1991) 
- André de Quadros The Cambridge Companion to Choral Music 2012 1107493390 p.156 "There has been a marked increase in choral compositions since the founding of the JCA ... Notable choral composers are Chihara Hideki, Hosokawa Toshio, Suzuki Teruaki, Kanno Shigeru, and Matsushita Ko; ..."
- Klangmächtige Kathedralen Gerd Döring in Frankfurter Rundschau, 2 September 2008 (in German)
- "Komponistenwerkstatt: Walter Fink zum 80. Geburtstag" (in German). Rheingau Musik Festival. 2010. Retrieved 5 August 2010.
- BIS Records
- Narazaki, Yoko. 2001. "Hosokawa, Toshio". The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell. London: Macmillan Publishers.