Cosgrove came to national fame in 1999 when, as a major general, he led the international forces (INTERFET) in a peacekeeping mission to East Timor. The mission's success made him one of Australia's most respected and popular military leaders. He returned to Australia in 2000 as Land Commander Australia, was promoted to lieutenant general in July and appointed Chief of the Army and, in 2002, was advanced to general as Chief of the Defence Force.