Steponas Kosmauskas was born on April 29, 1918 in Darbutai, Kaunas County, Lithuania, Ober Ost [now Raseiniai District Municipality, Kaunas County, Lithuania]. He was an actor, known for
Rokirovka v dlinnuyu storonu (1969),
Gyvieji didvyriai (1959) and
Zingsniai nakti (1962). He died on March 25, 1985 in Panevezys, Lithuanian SSR, USSR [now Panevezys County, Lithuania].