In 1976, he graduated from the Lithuanian State Conservatory. Vocational teachers - Gintas Žilys, Vlada Mikštaitė, Nadiežda Ogaj, Algė Savickaitė. He has been working at the Kaunas State Drama Theater since 1976. During the tours, the audience of Russia, Estonia, Georgia, Canada, Austria, Germany, Norway, Holland got to know J. Onaitytė's creative style. Created significant roles in television and cinema.