A Rhodes scholar, Turnbull first worked as a journalist after graduating from Sydney University in 1977, before practicing as a barrister. He rose to the public's attention nas the successful advocate in the Spycatcher trial (he blocked the British Government's attempts to suppress the memoirs of a former MI5 agent), and later authored a book on the trial.
From 1993 to 2000 Turnbull was the chairman of the Australian Republican Movement. He was an elected delegate at the Constitutional Convention in Canberra in February, 1998, and in 1999 published a book on the subject, entitled Fighting for the Republic.
In 1999, Turnbull invested in internet start-up Ozemail, which was subsequently sold to the telecommunications giant MCI Worldcom. Turnbull's stake was reportedly worth nearly A$60 million. Turnbull owns merchant banking company, Turnbull & Partners, and is a partner at the United States investment bank Goldman Sachs.
As of 2003, Turnbull is chair of a technology investment company, FTR Holdings, honorary treasurer of the Australian federal Liberal Party, and chair of the Canberra-based policy research organisation, Menzies Research Centre.
Turnbull is married, with two children, and lives in Sydney.