[3] Apart from acting, he also served as the Deputy Speaker of the Parliament of Sri Lanka from 1989 to 1994 and the Governor of the North Eastern Province from 1995 to 1998.

Fonseka married his longtime girlfriend Dorothy Margaret Valencia also known as "Tina" in 1962, and the couple had four children: Chamila, Thanuja, Dammith and Ishara.

Through his 6 children, Fonseka has 10 grandchildren: Yasara, Vivek, Indula,Daniel, Tarik, Janik, Hrithik, Ruveka and Tiasha.

He acted in many commercially successful films such as Chandi Rejina, Ira Handa Illa, Chandiyage Putha, Cheriyo Darling, and Raththaran Malli.

He originally wanted to be a cameraman and in this line worked as the second Assistant Director on David Lean's The Bridge on the River Kwai (1957) and Lester James Peries' Rekava (1956).

With films like Adata Wediya Heta Hondai, Ranmuthu Duwa, Getawarayo, and Dheevarayo, Fonseka achieved popularity and became a box-office draw.

[9] Seeking to not play in only commercial roles, Fonseka appeared as Jinadasa in the groundbreaking Gamperaliya (1964), working again with Peries.

[10] Fonseka's role as Willie Abeynayake in Nidhanaya (1972) and as ASP Wicrema Randeniya in Welikathara (1971) are widely considered to be his crowning achievements.