Esa Onttonen is a composer and guitarist living in Helsinki, Finland. He mainly works in the field of jazz and improvised music but is equally at home playing rock riffs on electric guitar or writing a piece for string orchestra. He is a co- leader of groups Gourmet and Gnomus which have released a total of nine albums and performed in Belgium, Estonia, France, Germany, Morocco, the Netherlands and Russia, in addition to several tours in Finland. His regular collaborators include saxophonist Mikko Innanen, drummer Mika Kallio and pianist Kari Ikonen. Along with Onttonen they are also the founders of the record label Fiasko Records.
Onttonen has written commissioned compositions and arrangements for soloists Jukka Gustavson, Mikko Innanen, Anna-Mari Kähärä, Mirja Mäkelä, Jukka Perko, Jenny Robson, Tomasz Stanko, and orchestras such as Finnish Radio Symphony Orchestra, UMO Jazz Orchestra, Virtuosi di Kuhmo, St. Michel Strings (Mikkelin kaupunginorkesteri), Uusinta Chamber Ensemble, Kaartin Seitsikko, Jyväskylä Big Band and Avanti! (with Badu Ndjai). He has worked in artist residencies in Paris, Rome and Prague.
As guitarist Onttonen has played and recorded with his own groups Gnomus and Gourmet and as sideman with Hepa Halme Prospekt, Mirja Mäkelä, Jukka Orma's Revolution Soul Band, Ari Poutiainen, Jenny Robson and many others. His versatile style ranges from traditional guitar aesthetics to uninhibited free improvisation utilizing a wide spectrum of sounds available from electric guitar and various effects.