He was elected to the National Assembly in 1991 and served until 1999, when he took office as a member of the Legislative Yuan.

Lai earned a bachelor's degree in political science from National Taiwan University,[1][2] where he met Liu Yi-te and Lee Wen-chung.

[3] In interviews, Lin credited the end of official relations between Taiwan and the United States and the Kaohsiung Incident, both of which occurred in 1979, for increasing his interest in politics.

[6] While serving on the Legislative Yuan, Lai was also president of the Taiwan Children's Rights Association.

[21][22] Lai was nominated for a second term on the Legislative Yuan in 2001, and won reelection as a DPP candidate.