In May 1962, Serong was selected to lead the 30-man Australian Army Training Team Vietnam (AATTV) of instructors to South Vietnam.
Serong had been appointed by Pollard—with whom he was close friends—and was given authority to act unilaterally.
He conducted a reconnaissance of South Vietnam in June, and the main body of the AATTV began arriving in early August.
Serong based his headquarters in Saigon; the rest of the team was located at various installations throughout the country.
Although the AATTV was mostly involved in training the South Vietnamese forces, a few had been attached to the Combined Studies Division, run by the CIA as a counter-insurgency organisation.
Serong later became a counter-insurgency advisor to General Paul Harkins, Commander US MACV, but this relationship ended under Pollard's successor, Lieutenant General John Wilton, who reduced Serong's autonomy while continuing to grant him considerable latitude.
In May 1963 Serong accepted an invitation to visit the US Special Warfare School in North Carolina, informing the Military Board only after doing so, and he later visited West Germany to become familiar with intelligence activities there, again without informing Wilton, who reacted angrily after finding out about it from a newspaper report.
Meanwhile, in late 1963, Serong started to redeploy members of the team into combat advisory roles, and by February 1964 some officers and NCOs were working with Special Forces teams involved in counter-insurgency operations.
Resulting in the first involvement of Australian personnel in combat during the conflict, this was a significant decision; it was retrospectively approved by Wilton, who lifted earlier restrictions on the role of AATTV personnel that had prevented them being involved in combat.

According to his biographer Anne Blair, Serong believed in the need to prevent the spread of communism throughout South East Asia, conceiving his mission in South Vietnam in terms of the Domino Theory.
In August 1964, Sir Walter Cawthorn, then head of the Australian Secret Intelligence Service (ASIS), had instructed Serong to "...Get me ten years...", time that had to be bought to strengthen the other nations of the region against insurgency, as well as to destroy the Soviet Union economically.
After handing over command of the AATTV to Colonel David Jackson in 1965, Serong remained in Vietnam as an advisor, seconded to the US Department of State.
In 1965 he was awarded the Distinguished Service Order (DSO) for "outstanding courage and devotion to duty" while commanding the AATTV.
During the two-and-half years he led the team he had worked hard to remain in personal contact with its members despite their geographic dispersion, and on occasion while visiting advisors in outstations he had become involved with clashes with the enemy during which his courage and leadership "contributed to the success of operations".
Serong declined a formal presentation of the award.
From 1965 to 1967 he was senior advisor to the South Vietnamese Police Field Force.
Serong left the Australian Army in August 1968, at which time he was granted the honorary rank of brigadier.

Blair later wrote that Serong had accepted the defence of South Vietnam from communism as his "personal mission", and his decision to take an early retirement had been due to his increasing involvement with US organisations, the value they placed on his work and his profile as an international figure, as well as a growing "emotional distance" from the Australian Army and its senior leadership.
He later wrote that he "... found a way of being of more service to the country outside it than in it."
Serong stayed in South Vietnam as a security and intelligence adviser to the Vietnamese government.
He also instructed at the National Defense College of South Vietnam and worked for the Rand organisation, Hudson Institute and other corporations, preparing strategic analyses.
He was also a consultant to the Pentagon and the policy planning teams of several US presidents, including the Nixon administration.
In 1971, Serong decla
In May 1962, Serong was selected to lead the 30-man Australian Army Training Team Vietnam (AATTV) of instructors to South Vietnam. Serong had been appointed by Pollard—with whom he was close friends—and was given authority to act unilaterally. He conducted a reconnaissance of South Vietnam in June, and the main body of the AATTV began arriving in early August. Serong based his headquarters in Saigon; the rest of the team was located at various installations throughout the country. Although the AATTV was mostly involved in training the South Vietnamese forces, a few had been attached to the Combined Studies Division, run by the CIA as a counter-insurgency organisation. Serong later became a counter-insurgency advisor to General Paul Harkins, Commander US MACV, but this relationship ended under Pollard's successor, Lieutenant General John Wilton, who reduced Serong's autonomy while continuing to grant him considerable latitude. In May 1963 Serong accepted an invitation to visit the US Special Warfare School in North Carolina, informing the Military Board only after doing so, and he later visited West Germany to become familiar with intelligence activities there, again without informing Wilton, who reacted angrily after finding out about it from a newspaper report. Meanwhile, in late 1963, Serong started to redeploy members of the team into combat advisory roles, and by February 1964 some officers and NCOs were working with Special Forces teams involved in counter-insurgency operations. Resulting in the first involvement of Australian personnel in combat during the conflict, this was a significant decision; it was retrospectively approved by Wilton, who lifted earlier restrictions on the role of AATTV personnel that had prevented them being involved in combat.
According to his biographer Anne Blair, Serong believed in the need to prevent the spread of communism throughout South East Asia, conceiving his mission in South Vietnam in terms of the Domino Theory. In August 1964, Sir Walter Cawthorn, then head of the Australian Secret Intelligence Service (ASIS), had instructed Serong to "...Get me ten years...", time that had to be bought to strengthen the other nations of the region against insurgency, as well as to destroy the Soviet Union economically. After handing over command of the AATTV to Colonel David Jackson in 1965, Serong remained in Vietnam as an advisor, seconded to the US Department of State. In 1965 he was awarded the Distinguished Service Order (DSO) for "outstanding courage and devotion to duty" while commanding the AATTV. During the two-and-half years he led the team he had worked hard to remain in personal contact with its members despite their geographic dispersion, and on occasion while visiting advisors in outstations he had become involved with clashes with the enemy during which his courage and leadership "contributed to the success of operations". Serong declined a formal presentation of the award. From 1965 to 1967 he was senior advisor to the South Vietnamese Police Field Force. Serong left the Australian Army in August 1968, at which time he was granted the honorary rank of brigadier.
Blair later wrote that Serong had accepted the defence of South Vietnam from communism as his "personal mission", and his decision to take an early retirement had been due to his increasing involvement with US organisations, the value they placed on his work and his profile as an international figure, as well as a growing "emotional distance" from the Australian Army and its senior leadership. He later wrote that he "... found a way of being of more service to the country outside it than in it." Serong stayed in South Vietnam as a security and intelligence adviser to the Vietnamese government. He also instructed at the National Defense College of South Vietnam and worked for the Rand organisation, Hudson Institute and other corporations, preparing strategic analyses. He was also a consultant to the Pentagon and the policy planning teams of several US presidents, including the Nixon administration. In 1971, Serong decla
Ted Serong