Joonas Lehtimäki was born in Raisio, in the south-west of Finland. He has an education as a school teacher and is also studying Visual Arts at Aalto University. His comics have been published in several magazines and anthologies, including Aino magazine and the Ilta-Sanomat tabloid.
He is best-known for his cult comic strip 'Anonyymit', that runs in Nyt, the entertainment supplement of the Helsingin Sanomat newspaper. Lehtimäki also teaches courses and workshops through the Helsinki Comics Center, and has worked as a comics publisher with the publishing house Naama since 2009.