Hailing from the Ostrobothnian town of Haapavesi, Okko Saastamoinen was bitten by a jazz bug when The Five Corners Quintet performed in the nearby town Oulainen in 2008. Having commenced his jazz studies under the tutelage of Simo Peltola and the HERD drummer Tuomas Timonen, Saastamoinen was accepted to the Jazz Department of the Sibelius Academy in 2014. At the academy, he has been taught by the likes of Panu Savolainen and Jussi Lehtonen. 

Saastamoinen leads his own quartet, O. Saastamoisen kvartetti.