[1] After leaving school, O'Neil moved to Sydney and began working with Angus & Robertson as a buyer, becoming head of art books.
Settling in Brisbane, in 1955 he was recruited by bookseller Brian Clouston to run schoolbook publisher Jacaranda Press.
[1] In December 1967, O'Neil was appointed by the McEwen government as deputy chairman of the newly created National Literature Board of Review, to advise the Minister for Customs and Excise on literary censorship.
[4] He subsequently established Lloyd O'Neil Pty Ltd, which initially partnered with Golden Press and Rigby Ltd to make use of their distribution networks.
In partnership with John Currey, O'Neil printed new editions of a number of out-of-print Australian titles.
[1] His youngest child Clare O'Neil was elected to federal parliament in 2013, while another daughter Helen O'Neil has served as executive director of the Council for the Humanities, Arts and Social Sciences and on the board of the Film Finance Corporation Australia.