Gardiner obtained his Bachelor of Arts degree in 1688, and became a Fellow of All Souls College in the following year.
Thomas Tenison, the Archbishop of Canterbury, nominated him to become the Warden (head) of All Souls in 1702.
He helped to organise the rebuilding of All Souls by Nicholas Hawksmoor and George Clarke.
Gardiner married Grace, the daughter and eventual heir of Sir Sebastian Smythe, Kt, of Cuddeston, Oxfordshire, physician to King William III, and died on 22 April 1726 in Oxford.
His estates were inherited by his daughter, also called Grace, who married Robert Whalley, MD in 1742;[4] for whose sons see Whalley-Smythe-Gardiner baronets.