Born on 8 July in 1969, Vievis. After graduating from school (he attended Vievis Secondary School) in 1985-1989 he studied saxophone at the Vilnius Juozas Tallat Kelpša Higher School of Music. From 1989 to 1993 he studied opera vocals at the Lithuanian Academy of Music and Theatre (under the guidance of Prof. Vaclovas Daunoras), and from 1994 to 1997 he studied acting (with a musical focus) at the course of J. Vaitkus.
The actor performed in plays by J. Vaitkus, E. Nekrošius, C. Graužinis, O. Koršunovas, and conducted classical music concerts for children. As a vocalist, he has performed works by A. Martinaitis, A. Kučinskas, A. Jasenka and G. Puskunigis. He still provides voice-overs for animated films (e.g. "Shrek", "The Princess and the Frog").
I. Jankaitis has been working at Vilnius Lėlė Theatre since 1998.