O'Neill, who has Turkish ancestry, was born in Cork, Ireland, in 1964, and grew up in The Netherlands, where he attended boarding school at The Hague. He read law at Girton College, Cambridge, preferring it over English because "literature was too precious" and he wanted it to remain a hobby. After a year off to write his first novel, O'Neill became a barrister at the English Bar, where he practised for ten years at The Temple, principally in the field of business law.
He is married to Vogue editor Sally Singer, who rejected his second novel when she was working as an editor at Farrar, Straus, and Giroux. They live in the Chelsea Hotel in New York with their three sons.
O'Neill is the author of three novels, the most recent of which, Netherland, was published in May 2008 and was featured on the cover of the New York Times Book Review where it was called, "the wittiest, angriest, most exacting and most desolate work of fiction we’ve yet had about life in New York and London after the World Trade Center fell". Literary critic James Wood called it "one of the most remarkable postcolonial books I have ever read". Among the books on the longlist, it was the favourite to win the Man Booker Prize. However, on September 9, 2008, the Booker nominee shortlist was announced, and the novel stunningly failed to make the list.
Additionally, O'Neill writes literary and cultural criticism, most regularly for the Atlantic Monthly.
Blood-Dark Track: A Family History (Granta Books) (2001)
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