Aslet was educated at Peterhouse, Cambridge, where he earned a degree in the history of architecture. After graduating, he joined Country Life magazine in 1977 as architectural writer, becoming architectural editor in 1984, deputy editor in 1989, and editor-in-chief in 1993. In 1997 he was named British Society of Magazine Editors' Editor of the Year. After 13 years as editor-in-chief, from 13 March 2006, Aslet left and took on a newly created role of editor-at-large, leading Country Life's important public relations activities and acting as an editorial consultant and writer for the magazine, as well as writing more books and doing freelance articles for newspapers such as the Daily Telegraph, the Daily Mail, and the Sunday Times, and broadcasts on radio and television current affairs programmes such as Newsnight.
Aslet lives in London and Ramsgate with his wife and three children.
The best buildings in Britain: a catalogue of grade 1 buildings and grade A churches in England, category A buildings in Scotland and Western Isles, grade 1 buildings and grade A churches in Wales / compiled by Iain Clark, Clive Aslet and Louise Nicholson; edited by Roger Coppen (Save Britain's Heritage, c1980)
Enchanted Forest: The Story of Stansted in Sussex (by The Earl of Bessborough, with Clive Aslet, Weidenfield And Nicholson, 1984) (ISBN 0297784919)
A history of Elveden (Christie, Manson & Woods Ltd, Sale catalogue, 1984)