Lysaght was educated in Dublin at Gonzaga College, at University College Dublin, and at Cambridge University. He qualified as a barrister at the King's Inns, Dublin, and then at Lincoln's Inn in London. He was one of the duo that won the first Irish Times Debate in 1960 and was elected auditor of the King's Inns Debating Society in 1961. He worked for the Irish Department of Foreign Affairs as a specialist in European Union law. He is President of the Cambridge University Ireland Society.
- Administration of Justice in Ireland (1975) by VTH Delany; edited by Charles Lysaght
- Brendan Bracken Allen Lane, London (1979) ISBN 0-7139-0969-2
- Edward MacLysaght, 1887-1986: A memoir (1988)
- Vanishing Kingdoms: Irish Chiefs and Their Families, AD 900-2004 (2004) (joint author)
- The Times Great Irish Lives: An Era in Obituaries (Times Books 2008-09), co-authored with Garret FitzGerald.