Born on 22 August 1933 at Bega, New South Wales, Jocelyn's father John Daniel Jocelyn was a police officer; both he and Jocelyn's mother Phyllis Irene (née Burton) were born in Australia, though John was descended from English migrants who settled in the goldfields and Phyllis from English and Irish convicts transported to Australia.
Supported by a travelling scholarship from Sydney, Jocelyn studied at St John's College, Cambridge (1955–57), completing part II of the classical tripos.
He received the Sandys (1957) and Craven (1958) studentships from Cambridge and was student at the British School at Rome from 1957 to 1959.
He published his doctoral dissertation as The Tragedies of Ennius in 1967 and was promoted to a professorship at Sydney in 1970.
[2] Though his Tragedies of Ennius would be his only book, he edited Festschrifts for Brink and his former Cambridge contemporary F. R. D. Goodyear; he also wrote over 80 articles, 50 chapters and other papers, and 130 reviews.