Egan holds a Bachelor of Science degree in Mathematics from the University of Western Australia. He published his first work in 1983. He specializes in hard science fiction stories with mathematical and quantum ontology themes, including the nature of consciousness. Other themes include genetics, simulated reality, posthumanism, mind uploading, sexuality, artificial intelligence, and the superiority of rational naturalism to religion.
He often deals with complex technical materials, like new physics and epistemology. He is a Hugo Award winner with eight other works shortlisted for the Hugos and has also won the John W. Campbell Memorial Award for Best Science Fiction Novel. His early stories feature strong elements of supernatural horror.
Egan's short stories have been published in various genre magazines, including regular appearances in Interzone and Asimov's Science Fiction. In 2018, Egan described the construction of super permutations, thus giving an upper bound to their length. On 27 February 2019, using ideas developed by Robin Houston and others, Egan produced a superpermutation of n = 7 symbols of length 5906, breaking previous records.
As of 2015, Egan lives in Perth. He is a vegetarian and an atheist. Egan does not attend science fiction conventions, does not sign books, and has stated that he appears in no photographs on the web. However, both SF fan sites and Google Search have often mistakenly represented photos of others with the same name as the writers.