[1][2] In the Foreign Service, he served in Vientiane where he worked with the US ambassador to Laos Charles W. Yost, Pretoria, and Bogotá, as well as with the Delegation to NATO in Paris.
[3][2] In 1967, he resigned from the Foreign Service and joined the publishers Collins, which was, at the time, run by his father-in-law.
[2] Originally intending to be a novelist, he began a career as biographer with his life of Talleyrand's lover, the Duchess of Dino.
Ziegler wrote for various journals and newspapers, including The Spectator, The Listener, The Times, The Daily Telegraph and History Today.
[3] In 1967, gunmen broke into Ziegler's family home in Bogotá and shot dead his wife, Sarah Collins.