Dharmaretnam had been a Vanniyar since the age of 17. He and his brother Rajaratnam owned large pieces of land in the old Batticaloa District, from Verugal to Pottuvil. Dharmaretnam's son Puvirajakeerthi (known as Keerthy or Dharmakeerthy) was one of the first Batticaloa Tamils to attend the University of Cambridge. Dharmaretnam was the paternal grandfather of Taraki Sivaram, a journalist murdered during the Sri Lankan Civil War.
