The central focus of Aho’s work consists of large-scale orchestral, chamber and vocal works; to date his output includes five operas (1978–2013), seventeen symphonies (1969–2017), twenty-eight concertos (1981–2016), three chamber symphonies for string orchestra, other orchestral and vocal music and a large amount of music for chamber ensembles and solo instruments.
He has also made a number of arrangements and orchestrations of works by other composers. The most important of these is the completion of Uuno Klami’s unfinished ballet Pyörteitä (Whirls). In 1992 the Lahti Symphony Orchestra appointed Kalevi Aho composer in residence, and since 2012 he has been its composer laureate.