James Hilton, 24, of Aberdeen, was trying to catch up with a friend who was travelling in another car on the A920 Dufftown to Huntly road in 2015.
Patrick Pirie, 81, of Dufftown, was in a car involved in the resulting crash. He died in hospital from his injuries.
Sentence on Hilton was deferred at the High Court in Aberdeen.
Hilton crossed on to the other carriageway and was involved in a head-on crash.
Great-grandfather Mr Pirie was travelling home from a farmers' mart in nearby Huntly when the collision happened.
Hilton had been visiting his own grandfather in hospital in Aberlour shortly before the crash.
Adovate depute William McVicar, prosecuting, said Hilton overtook two vehicles at speed and carried out the manoeuvre when he had "insufficient view of oncoming vehicles".
Tony Lenehan, defending, said Hilton had believed the road to be clear in front of him before he carried out the overtaking manoeuvre.
He acknowledged that his client's driving before the crash did not show him in a good light and said he was "enthused with the joy of driving".
He said Hilton had now been taught the lesson that car control skills were no substitute for care and driving experience.
Mr Lenehan said: "The enormity of the harm that he has done is in no way lost upon Mr Hilton and he implores me to extend his apologies to those who have most greatly been affected by it."
Hilton had one previous conviction, a speeding offence from 2011.
Sentence was deferred for background reports until 16 May at the High Court in Edinburgh.
A driver has admitted causing the death of a pensioner by driving dangerously while overtaking two vehicles on the approach to a corner on a country road.