Lim Kit Siang
Koh joined Gerakan in 1982. He won a parliamentary seat during the 1982 general election but lost it to Lim Kit Siang in the following 1986 general election. The following year, he was elected Gerakan Youth chairman. Koh was the protégé of then Penang Chief Minister Lim Chong Eu, serving as Lim's political secretary and chief aide from 1986 to 1990.