During that period, his artwork (usually black and white, though sometimes colour) was included in a variety of non-fiction books, science-fiction and horror magazines and other publications.
His earliest covers were for books by Australian writers Jacob G. Rosenberg, Alex Skovron, Walter Adamson, and Ian Kennedy Williams.
O'Keefe's illustrative work has appeared in many publications, including Aphelion, Crypt of Cthulhu, Culture Magazine (illustrated serial "Down the Rabbit Hole"), Eidolon, Esoterica, Phantastique, Scarp, Shadowplay, 24 Hours (Australian Broadcasting Corporation), Terror Australis, Theosophy in Australia and Wildfire.
His cover designs appear on Ian Kennedy Williams' Stopping Over (1988), Walter Adamson's The Man With the Suitcase (1989), Roslyn Taylor's Uncle Abe (1989), Peter Coaldrake and J.R. Nethercote's What Should Government Do?
O’Keefe has illustrated Philip José Farmer’s The Green Odyssey and Love Song, William Blake's An Island in the Moon (Purple Mouth Press), Aleister Crowley's The Poem and Leanne Frahm's Borderline (MirrorDanse Books).
Time Line: Selected Illustrations (Ramble House, 2010) collects a range of O'Keefe's illustrations from his first four decades, including designs inspired by the macabre stories of H. P. Lovecraft, Tod Robbins and Edgar Allan Poe, illustrations for science-fiction works by Richard A. Lupoff, Robert Sheckley and Philip José Farmer, drawings for the ‘nonsense’ stories of Lewis Carroll and Edward Lear, drawings inspired by the music of King Crimson, Queen and Brian Eno, cover illustrations for mystery novels by Chelsea Quinn Yarbro, Mark Hansom, Walter S. Masterman, Richard E. Goddard and Arlton Eadie, and a range of fairy and fantasy art.