Finland's Kalevi Aho is among the foremost contemporary composers. As of early 2021, his well-regarded, expansive catalog includes 17 symphonies, 35 concertos, five operas, and many other works. He is also a noted educator, conductor, and violinist.

Aho was born in Forssa, Finland, on March 9, 1949. His musical life began when he discovered a mandolin at his family's home and taught himself how to play. One of his school teachers, Martti Loikkanen, instructed him on mandolin and encouraged him to take up the violin as well. During this time, Aho also learned how to read music and quickly took to composing. He entered the Sibelius Academy in 1968, studying violin and composition; his composition teacher was Einojuhani Rautavaara. His first symphony, written in 1969, drew comparisons to Shostakovich and brought attention to the young composer. After receiving his composition degree in 1971, Aho continued his studies in Berlin under Boris Blacher at the Staatliche Hochschule für Musik und darstellende Kunst. He taught musicology at Helsinki University from 1974 to 1988, leaving to take the position of professor of composition at the Sibelius Academy, where he served from 1988 until 1993. In 1992, Aho was named composer-in-residence with the Lahti Symphony Orchestra, a position he held until 2012 when he was named composer laureate.

Aho's early works, particularly his first four symphonies, contain many elements of earlier musical styles, specifically counterpoint, and showed obvious influences from composers such as Shostakovich and Mahler. Aho's fifth symphony (1975/1976) began a notable shift away from his early style into a more modernist vein. His first opera, Avain, was written in 1978 and was followed by his sixth symphony (1979/1980), after which the composer's focus shifted away from symphonism for a time. Aho's output grew tremendously following his partnership with the Lahti Symphony, beginning with his eighth symphony from 1993. Aho's concerto output has incorporated a vast array of solo instruments, from the piano and violin to the less-traditional tuba and contrabassoon. He has also written for voice, including the song cycle Kiinalaisia lauluja, a very diverse collection of chamber ensembles, and is celebrated for his arrangements, orchestrations, and completion of works by other composers: among these is an orchestration of Bach's "Contrapunctus XI" from Die Kunst der Fuge, BWV 1080. In 2019, the Lahti Symphony premiered Aho's Symphony No. 17 ("Sinfonisia freskoja"). In 2021, Aho wrote his fourth string quartet on commission from the Lounais-Hämeen Musiikkipäivät Festival.

Many of Aho's works have been recorded; among these is a recording of his theremin and horn concerto, for which he won the 2015 ECHO Klassik Award. He has also earned the Henrik Steffens and Léonie Sonning Awards for composition and the Pro Finlandia Medal of the Order of the Lion of Finland. Aho is also an accomplished writer, having published several essays and co-written the books Music of Finland and Uuno Klami - Life and Works. ~ Keith Finke, Rovi