He excelled in numerous sports, including table tennis, basketball, and field hockey, when he was studying at Royal College.

He entered medical college in 1964 and continued to be engaged in multiple sporting activities, including table tennis, basketball, and field hockey, at the University of Ceylon.

[1] He also went onto take the leadership role during his academic career by captaining the Combined Universities team for both field hockey and table tennis during a mercantile invitational tournament which was held in India.

[1] Immediately after he became qualified as a doctor in 1971, he received a lucrative employment opportunity in New Zealand at a teaching hospital at Christchurch.

[4] In October 1977, he was appointed the doctor to Kerry Packer's World Series Cricket involving powerhouses Australia and the West Indies.

He had also notably provided consultancy services and guidance related to medical issues for Sri Lankan sportspeople prior to their participation at certain international sporting events in Australia.

[10] It was also revealed that some Sri Lankan cricketers, including Sanath Jayasuriya, Muttiah Muralitharan, Ravindra Pushpakumara, Nuwan Zoysa, Arjuna Ranatunga, and Chaminda Vaas, insisted on bringing Siri Kannangara on board as part of the Sri Lankan medical support staff prior to the start of the 1999 Cricket World Cup in England, but Kannangara turned down the offer due to potential scheduling difficulties involving his duties at a teaching hospital in Sydney.