Lauri Mäntysaari was born and raised in Helsinki but now lives in Turku. He composes music on a wide scale for both Finnish and foreign musicians. He has won international competitions at the Chamber Music Festival in The Hague (2012), the Milan Conservatory (2012) and the VocalEspoo Festival, and was one of 16 selected finalists at the Bartók World Competition 2022. His most extensive work to date is Vigilia, which was performed in its entirety for the first time by Key Ensemble on 18 April 2022.

Mäntysaari studied with Erkki Jokinen and Veli-Matti Puumala at the Sibelius Academy and in recent years has been particularly interested in spectral harmonies and the possibilities offered by microintervals. They appear, for example, in the suite of works Birdflight Impressions (2019-22) composed for Elisa Järvi and her quarter-tone piano, and in the monologue opera Loputtomuus (Endlessness, 2024).