He was born on 17th March 1948 in Singapore and attended the Jalan Daud Primary School, then Raffles Institution and the National University of Singapore, where he read Economics. He worked for a long time in Singapore Press Holdings before being seconded to the government sector, to Mendaki and MUIS.
He stood for the Singapore General Election under the PAP in 1997, under the then newly formed Cheng San GRC, against the Workers' Party, whose notable candidates were Mr JB Jeyaratnam and Tang Liang Hong. The PAP won that constituency.
Prior to his stint in Aljunied GRC, Zainul Abidin represented Cheng San GRC between 1997-2001. To date, he has sat on three select committees in Parliament.
Mr Zainul also held the post of Mayor of the NorthEast CDC from 2001 to 2008
He is currently the Senior Minister of State for the Ministry of Foreign Affairs.