The eldest in a family of six, Sze's career in the advertising and printing industry started in 1947 when he joined the Singapore Metal Printing & Manufacturing Co. as an assistant artist. In 1950, he joined the Malay Tin Print Co. for about a year before moving to Tiger Press as an artist and eventually becoming the Chief Artist at Tiger Standard.
Sze left for the advertising industry in 1955 where he first joined Progress Advertising and then Young Advertising (later renamed LPE Singapore) four years year. In both, he served as a chief artist. After five and a half years, Sze was appointed production manager in 1965. A year later, he became the studio manager. In 1982, Sze was found guilty of accepting bribes totaling nearly $120,000 from Tien Wah Press. He was then a production director with Batey Advertising.
Sze was active in helping nurture Singapore's nascent advertising and graphic design industry. He was a member of the Creative Circle, the Singapore Commercial Art Society and also helped Sin Chew Jit Poh in organising the National Graphic Art Competition. He was also a member of the Singapore Production Management Association (生產管理協會), set up in 1966 to promote scientific production methods and served as its president from 1971.
His two other brothers also worked in the advertising and printing industry.