His debut solo piano recording for Decca, of the cycles of preludes by Dmitri Shostakovich and Charles-Valentin Alkan, won both the Gramophone and Edison Awards. In addition to Decca, he has also made recordings for RCA and Ondine, notably of works by Beethoven and various modern Russian composers. Mustonen has performed with numerous major international orchestras and is regarded as "one of the internationally best-known pianists of his generation."[2]
As a composer, his work shows a "predilection for contrapunctally interwoven compositions and works of the 20th century which take up ideas from the 17th and 18th centuries, for example the Bach arrangements by Ferruccio Busoni and the cycles of preludes and fugues by Shostakovich, or Ludus Tonalis by Paul Hindemith."[4]
A Portrait of Olli Mustonen [as composer and pianist]: Fantasy for Piano and Orchestra (Ostrobothnian Chamber Orchestra/Juha Kangas); Six Bagatelles for Piano; Three Preludes for Piano; Ballade for Piano; On all Fours for Piano Four Hands (Raija Kerppo, hands 3 and 4); Three Simple Pieces for Cello and Piano (Martti Rousi, cello); Gavotte for Piano; Two Meditations for Piano; Toccata for Piano, String Quartet and Double Bass (Orion String Quartet; Esko Laine, double bass) – Finlandia Records (1989/1990)
Symphony No. 1 Tuuri (2012) for baritone and orchestra
Symphony No 2, Johannes Angelos (2013)
Symphony No 3, Taivaanvalot (Heavenly Lights) (2020)[7]
String Quintet No. 1 (2015)
String Quartet No. 1 (2017)
His composition style combines elements of the neo-classical, neo-baroque and romantic idioms, and he has also used minimalist patterns: 'The Baroque elements echo Stravinsky's Pulcinella or the stylizations of Martinů or Ottorino Respighi; these elements dominate the vivacious and rhythmic fast movements, whereas the slow movements are emphatically Romantic.'[8]