Early life and education
Wu was born on 19 June 1939 in Zhongli, Taoyuan, the third of eight sons. He belonged to a prominent Hakka Chinese family whose ancestral home was in Yongding, Longyan, Fujian. His father, Wu Hong-lin (吳鴻麟; 1899–1995), was a surgeon who graduated from Taihoku Imperial University, worked in the Japanese Red Cross Society, and began practicing ophthalmology in 1930. His mother, Lin Fang-lan (林訪蘭), came from a prominent family in Toufen and held leadership positions in several women's organizations in the Zhongli area. His grandfather, Wu Rongdi (吳榮棣; 1863–1937), attained the Qing imperial examination rank of xiucai in 1892 and founded a poetry society in Zhongli in 1921.
After World War II, Hong-lin served as speaker of the Taoyuan County Council and as magistrate of Taoyuan County from 1960 to 1964. When Wu as a child, his uncle Wu Hung-chi (吳鴻麒), a judge on the Taiwan High Court and the twin brother of Wu's father, was arrested and killed during the February 28 incident in 1947.
After elementary school, Wu moved to Taipei to attend the Affiliated Senior High School of National Taiwan Normal University (HSNU). After graduating from HSNU in 1958, he enrolled at National Cheng Kung University (NCKU) to study industrial management and business management. He graduated in 1962 with a bachelor's degree in management science. While an undergraduate, Wu joined the Kuomintang in 1961.