Sean McMullen has a rich ancestry that includes Scottish, Portuguese, French and Irish forebears. His first career was music, learning guitar as a teenager, appearing in student theatre and then turning to folk music in 1972. He performed as a guest singer in the 1973 production of the Pirates of Penzance and in 1974 he sang with the Victorian State Opera. He has also sung with the Melbourne University Choral Society, the Trinity College Consort and various other musical groups. In 1975 he took up instrument building, and still plays a 13-string lute that he constructed.
In 1974 McMullen graduated from the University of Melbourne in physics and history and went on to complete a postgraduate diploma in library and information science. In 1978 he spent time in Europe, singing and playing at folk festivals but gave up professional music on his return to Australia.
McMullen's science fiction stories were first published in amateur magazines in 1981. While undertaking a Master's degree, he was elected editor of the Melbourne University's SF Club's fiction magazine Yggdrasil. In 1985 at the World SF Convention he won the convention's writing competition with his short story 'The Deciad'. Since then his stories have appeared in Analog, InterZone, Fantasy & Science Fiction, Eidolon, Aurealis and numerous anthologies. McMullen established himself in the American market in the late 1990s and his work has been translated into many languages including Polish, French and Japanese. McMullen was an assistant editor and primary contributor to The MUP Encyclopaedia of Science Fiction & Fantasy (1998).
McMullen's work includes Voyage of Shadowmoon (2002), a sea-faring fantasy; The Eyes of the Calculor (2001), featuring disparate characters in the future; The Miocene Arrow (2000) and Centurion's Empire 1998), a high-tech SF tale of future intrigue. The settings for his work range from the Roman Empire to cities of the distant future. He has won numerous awards and his writing is well-regarded as being scientifically accurate and sits within the 'hard' science fiction milieu.
In 2008 McMullen submitted his doctoral thesis, comparing medieval stories with twentieth century movies with medieval settings, to the University of Melbourne
