Born in Taihe Village (太和村), Dongshan Township (冬山鄉), Yilan County, Taiwan, Yu studied international commerce at the Chih Lee College of Business (致理商專, now Chihlee Institute of Technology), Taipei in 1975. He graduated with a Bachelor of Arts in politics in Tunghai University in 1985.

His political career includes:

• 1981: Member of the Taiwan Provincial Assembly
• 1983 - 84: Dangwai Secretary-General
• 1984 - 86: Member of the Central Committee (中央常務委員) of the Democratic Progressive Party
• 1989 - 97 Chief magistrate of Yilan County for two consecutive terms
• 1998 - 99: Chairman of Taipei Rapid Transit Corporation