He arrived in South Vietnam in January, 1969 as officer commanding 2 Platoon, A Company.
In March, 1969, 2 Platoon suffered twenty casualties on enemy mines at the beginning of an operation. Displaying outstanding leadership Second-Lieutenant Brett continued the operation with one third of his platoon strength and deliberately sought out the enemy on every possible occasion in an endeavour to quickly restore confidence in his few surviving men. He successfully led his men several times against enemy entrenched in bunkers and skilfully planned and executed ambushes. During all contacts Second Lieutenant Brett was foremost, leading his men, directing their actions and leading sweeps and follow up actions.
In June, 1969, 2 Platoon was operating against an enemy main force company. Second Lieutenant Brett located the enemy bunker camp and calmly deployed his troops to ambush the superior size enemy force. So successful were his actions over several days that five enemy were killed and the remainder forced to abandon their camp. Again second Lieutenant Brett was to the front in the actions, placing himself in the most dangerous positions.
In November, 1969, an unknown size enemy force approached a 2 Platoon ambush position from the rear. Fire was opened by the one man in 2 Platoon who could see the enemy in thick jungle. Such was the aggressiveness of 2 Platoon under Second Lieutenant Brett that he adjusted fire positions during the fire fight and led an immediate pursuit. As a result four enemy were killed.
As a young officer he has shown professional skill of the highest order. Through his determined and aggressive leadership throughout 1969, he has gained the admiration of his platoon, his company and his battalion. His actions reflect great credit on himself and The Royal Australian Regiment.