Hathaway grew up on an estate near Oxford, Crevcour Hall, the son of the estate manager he mixed with those from the house but was never quite one of them fitting in well with neither the children of the servants nor those of the lord of the manor. Thanks to his own intelligence and likely the generosity of the marques Hathaway was sent to Harrow at age 12 leaving behind his parents and sister Nell. As would be a trend in his life he was considered aloof and a bit apart by the other boys at school, who called him Wolfgang Christ - because he didn't know whether he wanted to be Mozart or Jesus. He then went on to study at Cambridge, going away to college despite his mother being in poor health choosing to stay away rather than return to Crevcour Hall. At Cambridge he studied theology, and was a member of the rowing team, picking up yet another nickname - Attaway Hathaway.
He made his mark at Cambridge, to the point where his name is familiar to theologians at Oxford, and he was recruited by MI-5, but he had other plans and following completion of his degree he returned to Oxford and joined the seminary with the intent to become a priest. During this time an old friend came to him struggling with his homosexuality, and James' by the 'book' response sent the other man deeper into self loathing that would eventually end tragically. Disgust at his own blind faith and remorse at having met a please for help with heartless scripture-based condemnation ultimately led to him leaving the seminary.
Seeking a place for himself in the world he applied to the police and soon found himself the right had to a prickly, not entirely by the book DI named Lewis after his own DI was shopped for driving under the influence. His educational background and obvious intelligence often result in him being described as a funny sort of policeman but his erudite and deep thinking approach to crime solving ends up being a good compliment to Lewis' more experienced go with your gut kind of detection.