Leslie was born on September 1st, 1960. Leslie's father was Swee Keng Ong and his mother was Greta Gek Neo Tan. His maternal grandfather is Dr Chong Yan Tan and his maternal grandmother was Grace Chim Neo Chia. He had two brothers and a sister, named Derrick, Raymond and Serene. He died in an accident or as a result of an injury, Bicycle accident on Bukit Timah Road, at the age of 61 on November 29th, 2021 in Singapore.