Nathan Filer, 32, who studied for an MA in creative writing at Bath Spa University before becoming a lecturer at the institution, has had poetry broadcast on BBC Radio 4 and written and appeared in a short comedy film, Oedipus.
But it was The Shock of the Fall, his novel about a Bristol boy who slips into schizophrenia after the death of his brother and eventually finds himself in a psychiatric ward, which attracted a huge bidding war and was published by Harper Collins to huge acclaim in 2013.
It went on to win the first novel category in the Costa Book Awards earlier this month, making it automatically eligible for the main prize, which is selected from the winners of each category.
On 28 January Mr Filer secured the £30,000 prize, ahead of best-selling novelist Kate Atkinson (for her eighth novel, Life After Life), biographer Lucy Hughes-Hallett (for The Pike: Gabriele d’Annunzio: Poet, Seducer and Preacher of War) and two others.
Mr Filer’s success also marks a hat-trick for Bath Spa. The 2011 Costa Book of the Year award was won by former lecturer in creative writing, Andrew Miller, for his novel Pure, while the 2012 award (as well as the Man Booker Prize) was won by honorary graduate Hilary Mantel for Bring Up the Bodies.
This year’s Costa awards attracted a record 617 entries.
