In 1995, he was the only pre-qualified Sri Lankan engineer to bid for the 2.6 billion Marriott renovation of the Galle Face Hotel.
[citation needed] In addition to his construction ventures owned other commercial enterprises, such as the Glass House Health Center and Diagnostic Laboratory, a printing press, and a food manufacturing company.
He was a prominent real estate mogul, having invested in a famed billion-rupee multi-acre property in Sri Lanka's capital.
Gunasekera was elected Fellow and President of the Institute of Engineers, Sri Lanka for five consecutive years, later serving as the chairman of its board of trustees.
They had three children, Srimani who became a doctor, son Dhammika, who became an engineer and younger daughter, Sushila, was a prominent tennis player in the early 1970s before attending university to study architecture.