TERRY Moran has resigned as the nation's chief public servant
The new top Defence bureaucrat will be Duncan Lewis, who was an army officer for 30 years and former head of Special Forces before becoming a public servant and the first-ever national security adviser in 2008.
It is a rare move to make a former military person the civilian head of Defence.
Mr Moran, who was promoted to the top job by Kevin Rudd and stayed on under Julia Gillard, will stand down as head of the Prime Minister's Department on September 5.
He is a former head of the Victorian Premier's Department and has been a top-level public servant for 24 years. Ms Gillard said Mr Moran told her in January he wanted to retire.