Unnikrishnan was born to K. Radhakrishnan and Dr. Harini Radhakrishnan. He went to Asan Memorial Senior Secondary School, Chennai, in 1983. He graduated from Ramakrishna Mission Vivekananda College, Chennai, and received his B.Com degree from the Madras University. He earned a General Law and Post Graduate Diploma in Personnel Management and Industrial Relations. He worked as an executive in Parry s Confectionery Ltd. from 1987 to 1994. He is married to Priya, a Bharathanatyam and Mohiniyattam dancer and a native of Kozhikode, Kerala. They were married on November 1994 and have a son named Vasudev Krishna and a daughter named Uthara. Uthara won National award for playback singing for her debut song "Azhagu" in the movie "Saivam". He was initiated into Carnatic Music at age of 12 by Seshadri, Unnikrishnan. He was inspired by Sangita Kalanidhi Dr. S. Ramanathan. He is a national award winning playback singer for his debut film songs "Ennavale Adi Ennavale" and "Uyirum Neeye". These songs were composed by A. R. Rahman, with whom Unni Krishnan gave most of his memorable songs. In 2008, he presented a novel jazz concert in Thiruvananthapuram with the Eli Yamin Jazz Quartet and pianist Anil Srinivasan.