Parthasarathy was born in Madras, British India to civil servant, S. Soundararaja Iyengar. Soundararaja Iyengar was the second son of Sesha Iyengar; he was the younger brother of S. Srinivasa Raghavaiyangar and the elder brother of S. Kasturi Ranga Iyengar. Parthasarathy had his education in Madras and joined The Hindu as sub-editor in September 1924.
