Hans-Otto Ehrström studied at the Sibelius Academy and the Lyon Conservatoire, obtaining his solo diploma with distinction in 1998. He has been an official accompanist for all the major Finnish singing competitions and has himself, with his Lied partner, been the winner of the Pentti Koskimies Lied Competition.
In 1998–2000 Hans-Otto Ehrström was répétiteur at the International Opera Studio in Zurich. He has held the corresponding post at the Finnish National Opera, where he has also been an assistant conductor, since 2000 and at the Savonlinna Opera Festival since 2003.
His appearances in solo, chamber and Lied repertoire have taken Hans-Otto Ehrström to most parts of Europe and to Russia, Greenland, Israel and Japan. He has recorded in a variety of ensembles for both radio and television in Finland, Hungary and Croatia and can be heard on disc accompanying songs by Kuula, Schubert, Musorgsky, Sibelius and others.