Ramanathan was born on 16 April 1851 at the home of his maternal grandfather A. Coomaraswamy on Sea Street, Colombo in south western Ceylon.

[6] Ramanathan married Sellachchi Ammal, daughter of Mudaliyar E. Nannithamby, in 1874 at Ward Place, Colombo.

[14] Ramanathan was appointed to the Legislative Council of Ceylon in 1879 as the unofficial member representing Tamils, replacing his maternal uncle Muthu Coomaraswamy.

[17] Whilst on a tour of Europe Ramanathan, his wife, and his daughter were presented to Queen Victoria, and he was called to the bar at the Inner Temple in 1886.

[21] Ramanathan wrote a book during this period, published under his Shaivite holy name of Sri Parananda and titled An Eastern Exposition of the Gospel of Jesus according to St. John (1902), in which he argued that the teachings of Christ could be understood as instructions in yoga.

[1][28][29][30] Ramanathan was responsible for the release of the Sinhalese leaders who had been arrested following the 1915 Ceylonese riots, travelling to the UK to make their case.

[1][40] In 1907 Ramanathan rebuilt the Sri Ponnambala Vaneswara Temple at Sea Street in Kochchikade, founded by his father.

[48] Ramanathan opposed extending voting rights to the people and urged reservation of franchise only to men of the Vellalar caste.