[2] Lim was educated at Catholic High School and National Junior College before graduating from Loughborough University in 1976 with a first class honours degree in electronics, computer and systems engineering under a scholarship conferred by the Singapore Armed Forces (SAF) in 1973.

Lim made his political debut in the 1997 general election as part of a five-member PAP team contesting in Tanjong Pagar GRC, led by Prime Minister Lee Kuan Yew and was elected in a walkover.

Lim served as Deputy Secretary-General of the National Trades Union Congress (NTUC) from 1997 to 1999.

Lim was made a member of the PAP's Central Executive Committee in 1999 and served as the chairman of the party's youth wing between 2000 and 2004.

[6] Lim married to Elaine Cheong Siew Boon (born 1952) in 1981, introduced by a mutual friend.