The daughter of a high official, she was one of the few obese women in Chinese history to have been considered beautiful. She became a concubine to Xuanzong's son, but the 60-year-old emperor found the girl so desirable that he forced his son to relinquish her. Soon her two sisters were admitted into the imperial harem, and her brother Yang Guozhong became the first minister of the empire.

Through Yang's influence, An Lushan, a cunning young general of Turkish origin, rose to great prominence. Yang adopted him as her legal son and is said to have made him her lover. With such powerful patronage, An Lushan came to control an army of 200,000. He was jealous of the power of Yang's brother and soon turned against the emperor, leading a great uprising (the An Lushan rebellion) against him. When the capital was captured in 756, Xuanzong and his court were forced to flee to the south. On the road the imperial soldiers became enraged with members of the Yang family, whom they blamed for the debacle, and executed both Yang and her brother.