Jaakko Mäntyjärvi (b. 1963, Turku, Finland) studied English and Linguistics at the University of Helsinki, graduating with an FK (MA) degree in 1991. He is accredited as an Authorised Translator from Finnish to English and English to Finnish. He has also studied theory of music and choir conducting at the Sibelius Academy.

As a composer, Jaakko Mäntyjärvi describes himself as an eclectic traditionalist: eclectic in that he adopts influences from a number of styles and periods, fusing them into his own idiom; traditionalist in the sense that his musical language is based on a traditional approach and uses the resources of modern music only sparingly. Because he is himself active in making music, his music is very practically oriented; he is a choral singer, and thus most of his works are for choir. His major choral works include Four Shakespeare Songs (1984), Dagen svalnar... (Day is cooling, 1991/1993), Pseudo-Yoik (1994), El Hambo (1997), More Shakespeare Songs (1997), the choral drama SALVAT 1701 (2001), the 40-part Tentatio (2006) and Stuttgarter Psalmen (2009); Canticum Calamitatis Maritimae received 3rd prize in the European composition competition for cathedral choirs in 1997. 

His major commissions include works for the Cork International Choral Festival (1999), the 700th anniversary of the consecration of Turku Cathedral (2000), the World Symposium on Choral Music (2008), Chanticleer (2001), and the King’s Singers (2002). He was composer-in-residence of the Tapiola Chamber Choir from 2000 to 2005.

Jaakko Mäntyjärvi has been active as an amateur and semi-professional musician, mainly as a choral singer with a number of Finnish choirs, including the Savonlinna Opera Festival Choir, the professional Sibelius Academy Vocal Ensemble, the Tapiola Chamber Choir, the Klemetti Institute Chamber Choir, and the Finnish Chamber Choir. He conducted the Savolaisen Osakunnan Laulajat student choir from 1988 to 1993 and was deputy conductor of the Tapiola Chamber Choir from 1998 to 2004. He has also taught a course in the history of choral music at the Sibelius Academy in Helsinki.