Hristos Koromilas was born in Larissa where he received his first lessons in music. He graduated from the Attiko Conservatory of Athens / Double bass department - classical doublebass Diploma. He studied jazz double bass and jazz improvisation at the the Atheneum Conservatory of Athens with Sylvios Syrros and has received electric bass lessons by Yiorgos Zikoyiannis.

He has participated in numerous projects, concerts and festivals around Greece and Europe as a session bassist and a member of bands such as les Quintets and Pyros Ether, Ghost Notes etc. supporting different musical genres (jazz, contemporary, ethnic, world, pop) and has also collaborated on the Gazarte stage with guitarist Stochelo Rosenberg of the Rosenberg trio.