He was the third son of Robert Foulkes of Llechryd, Denbighshire, deputy baron of the court of exchequer of Chester, by Jane Ameredith of Landulph, Cornwall.
He was chosen censor at Christ Church in 1703, in preference to Edmund Smith, the poet, and was junior proctor for 1705.
His cousin William Jane, who died in 1707, left him wealthy as residuary legatee and devisee of his property, which included land in Liskeard and Bodmin; consequently he was a grand compounder for the degrees of B.D.
While an undergraduate he published, with John Freind and under Henry Aldrich's auspices, an edition of ‘Æschines against Ctesiphon and Demosthenes on the Crown,’ with a Latin translation (Oxford, 1696).
He married first in 1707 Elizabeth Bidgood of Rockbeare, Devon, who died in 1737; and secondly, on 26 December 1738, Anne, widow of William Holwell, and daughter of Offspring Blackall, bishop of Exeter.