Arjun Sarja was born on 15 August 1962, to a Kannada family in Madhugiri, in the erstwhile Mysore State. His father was Shakthi Prasad, a Kannada film actor, and his mother was Lakshmi, an art teacher. He had one elder brother Kishore Sarja, who directed Kannada films. He is married to Niveditha Arjun a former actress who has appeared in the 1986 Kannada film Ratha Sapthami under the stage name of Asha Rani. Kannada actor Rajesh is his father-in-law. Sarja has two daughters, Aishwarya and Anjana. Aishwarya Arjun made her acting debut in 2013. His nephews Chiranjeevi Sarja and Dhruva Sarja both act in Kannada movies. Another nephew of Arjun, Bharat Sarja, will also be making his acting debut in 2013.
Sarja, inspired by Bruce Lee’s 1973 film Enter the Dragon, began training Karate at the age of 16 and now holds a black belt.