 He studied linguistics until 1950.In 1955 Zinkevičius defended his thesis "Lietuvių kalbos įvardžiuotinių būdvardžių istorijos bruožai" ("Historical traits of adjective pronouns in Lithuanian language") and received a Doctoral degree.From 1956 to 1962, Zinkevičius was Dean of the Faculty of History and Philology of Vilnius University.