His father Anthony Marlay was a recent arrival in Ireland from Newcastle-upon-Tyne, where Thomas's grandfather Sir John Marlay (1590-1673) had been a leading local politician, who served as both Mayor of Newcastle and its MP; he is chiefly remembered for his spirited defence of the town against the invading Scots army during the English Civil War.
He rapidly built up a large practice at the Irish Bar, although Elrington Ball states that he was not very highly regarded as a lawyer.
An anonymous pamphlet from 1730, which took a somewhat jaundiced view of the Irish Bar in general, described him as "a sage refined": whether this tribute to his intellect was ironic or not is unclear.
He was a popular figure and his death seems to have been genuinely mourned: a Dublin paper published verses praising his gentleness, perfect manners and scholarship (the last being rather unusual among Irish judges of the time).
[4] In politics he was a staunch conservative, as demonstrated by his stern and contemptuous attitude to the radical doctor, politician and pamphleteer Dr. Charles Lucas (1713-1771).
"The scribbler, the impostor, has fled from Justice", Marlay told the grand jury: "His works (but I hope not his influence) remain".
[5] Marlay began the rebuilding of Celbridge Abbey in County Kildare, which is chiefly remembered as the home of Esther Vanhomrigh, the beloved Vanessa of Jonathan Swift.