He was a descendant of Matthew Grant, a Scotchman, who settled in Dorchester, Massachusetts, in 1630.
His earliest teacher (omitting the legendary Scotchman Menzies) was the dyak, or clerk of the council, Nikita Zotov, subsequently the court fool, who taught his pupil to spell out the liturgical and devotional books on which the children of the tsar were generally brought up. After Zotov's departure on a diplomatic mission, in 1680, the lad had no regular tutor.
At the Dutch university, where he matriculated on the 27th of October 1745, he associated with a small knot of English youths, afterwards well known in various circles of life, among whom were Dowdeswell, his subsequent rival in politics, Wilkes, the witty and unprincipled reformer, and Alexander Carlyle, the genial Scotchman, who devotes some of the pages of his Autobiography to chronicling their sayings and their doings.