|Born||30 May 1947|
|Alma mater||Trinity College, Oxford|
University College London
|Institutions||Christ's College, Cambridge|
|Doctoral advisor||A. A. Long|
Sedley was educated at Trinity College, Oxford where he was awarded a first class honours degree in Literae Humaniores in 1969. He was awarded a PhD in 1974 by University College London for a text, translation and commentary on Book XXVIII of Epicurus' On Nature.
He is the younger brother of Sir Stephen Sedley.
Since 1976 Sedley has been a fellow of Christ's College, Cambridge; from 1996 he was Professor of Ancient Philosophy at Cambridge University before in July 2000 being elevated to the Laurence Professorship of Ancient Philosophy. He retired from this position at the end of September 2014. He was succeeded in this post by his former student, Gábor Betegh.
- The Hellenistic Philosophers (with A. A. Long), Cambridge 1987
- Lucretius and the Transformation of Greek Wisdom, Cambridge 1998
- The Cambridge Companion to Greek and Roman Philosophy, Cambridge 2003
- Plato's Cratylus, Cambridge 2003
- The Midwife of Platonism. Text and Subtext in Plato's Theaetetus, Oxford 2004
- Creationism and its Critics in Antiquity, Berkeley and Los Angeles 2007
- Pyrrhonists, Patricians, Platonizers. Hellenistic Philosophy in the Period 155-86 BC (edited with A. M. Ioppolo), Naples, 2007