[4] His mother was a secondary school teacher[5] and his father was a senior lecturer at the University of Glasgow and Chairman of the city's Goethe-Institut.

[4][1] At the University of Oxford, Gardner received his BA, BCL (winning the Vinerian Scholarship), MA, and DPhil, under the supervision of Joseph Raz and Tony Honoré.

[8] In 2000, at the age of just 35, he was appointed Professor of Jurisprudence at Oxford, taking over the chair previously held by H. L. A. Hart and Ronald Dworkin.

[2][11] Gardner held several visiting positions, including at Columbia (2000), Yale (2002–3, 2005), Princeton (2008), the Australian National University (2003, 2006, 2008), and most recently Cornell (2015).

[8][7] A (non-practising) barrister since 1988, Gardner was elected an (Academic or Honorary) Bencher of the Honourable Society of the Inner Temple (one of the Inns of Court) in 2003.