John Le Gay Brereton was born in Sydney and educated at Sydney Grammar and the University of Sydney, taking a BA in 1894. After a variety of jobs, Brereton was appointed assistant librarian at the University of Sydney in 1902. By this time he had published two books of poetry and prose. He added to this with more volumes of poetry, such as Swags Up (1928), and many highly regarded scholarly articles on Elizabethan drama. In 1921 he was appointed professor of English literature and he was a foundation member of the English Association in 1923.
Brereton is not widely regarded as a major writer, but his verse has a significant place in the development of Australian poetry. He was a close friend of Henry Lawson and was well-known in many literary circles, giving advice and encouragement to many young writers and artists.
Brereton married in 1900 and raised four sons and a daughter. He died near Tamworth in 1933 while on a caravan tour.