Dennis James Richardson, AC (born 14 May 1947) is an Australian retired public servant and diplomat. His last appointment was Secretary of the Department of Defence (2012–17).
In 1969 Dennis Richardson commenced what would prove to be an outstanding career in the Australian Public Service. Between 1969 and 1986, he had various positions in the Department of Foreign Affairs, including postings to Kenya, Papua New Guinea and Indonesia.
In 1986 he was appointed Head of the Refugee and Humanitarian Branch in the Department of Immigration and Ethnic Affairs.
In 1987, he moved to the Department of Prime Minister and Cabinet, appointed Head of the International Division in 1988.
In 1990-91, he was seconded to Prime Minister Bob Hawke's office, where he served as Chief of Staff.
In 1992, Dennis reviewed the Australian Intelligence Community Post Cold War and
In 1993, he was appointed Deputy Secretary of the Department of Immigration and Multicultural Affairs.
Dennis was the 10th Director-General of Security from 1996 to 2005 and the 19th Ambassador of Australia to the United States of America from 2005 to 2010. He was appointed Secretary of the Department of Foreign Affairs and Trade, a position he held from 2010–2012 and in October 2012, Dennis was appointed Secretary of the Department of Defence, a position he held until 12 May 2017.
