Ilmo Ranta studied at the Sibelius Academy with Liisa Pohjola and received his diploma in 1984. He went on to complete further studies in Munich with Klaus Schilde and with György Sebök, Dmitri Bashkirov, Ralf Gothóni and Hartmut Höll. Currently Ranta teaches chamber music and piano at the Sibelius Academy.

Ilmo Ranta gave his debut concert in 1985. He has since given numerous solo recitals and has performed as soloist with the most important orchestras in Finland. Ranta has a strong reputation as a versatile chamber musician both in Finland and abroad. He is recognised as a first-class Finnish Lied pianist, who has regularly performed with singers such as Karita Mattila, Monica Groop, Jorma Hynninen and Petteri Salomaa. Ranta has also made several recordings with singers for BIS and Ondine among other labels.

Ranta is a widely appreciated performer of modern music and has performed several world premiere works by Usko Meriläinen, Paavo Heininen, Jouni Kaipainen and Eero Hämeenniemi, among others. He has also recorded new Finnish music with flutist Mikael Helasvuo. Some of his most significant solo recordings include The Second Piano Concerto with the Helsinki City Orchestra and Pluton for piano and electronics by Paavo Heninen. In 1996-1991 Ilmo Ranta was the artistic director of the Joroinen Music Festival and of the Sibelius Academy Concert Series.