Faiz Siddiqui alleges “inadequate” teaching on his modern history course resulted in him getting an upper second degree in June 2000.
He blames staff being absent on sabbatical leave and is suing the university for £1m.
Oxford denies negligence and causation and says the case is “massively” outside the legal time limit.
Mr Siddiqui also alleges medical information about him was not submitted to examiners by a tutor.
The 39-year-old studied at Brasenose College and singled out the teaching on the Indian special subject part of his course for criticism.
His counsel Roger Mallalieu told Mr Justice Foskett that Mr Siddiqui had been a “driven young man” aiming at a postgraduate qualification at an Ivy League university.
He said: “Whilst a 2:1 degree from Oxford might rightly seem like a tremendous achievement to most, it fell significantly short of Mr Siddiqui’s expectations and was, to him, a huge disappointment.”
Mr Mallalieu said his employment history in legal and tax roles was “frankly poor” and he was now unemployed, rather than having a career at the tax bar in England or a major US law firm.
Mr Siddiqui also said his clinical depression and insomnia have been significantly exacerbated by his “inexplicable failure”.
Julian Milford, for Oxford University, told the court Mr Siddiqui complained about insufficient resources, but had only described the teaching as “a little bit dull”.
He added the student received exactly the same amount of teaching as he would have in any other year.