Unnikrishnan was initiated into Carnatic music at age of 12 by V. L. Sheshadri. He was inspired by Sangita Kalanidhi Dr. S. Ramanathan. He attended a special workshop for six months on "Veena Dhanammal Bhani" under Sangeetha Kalanidhi T. Brinda and Sangeetha Kalanidhi Dr. T. Vishwa Nathan. 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 Unnikrishnan gave most of his memorable songs. He is the first male playback singer to be awarded the national award for a Tamil song. He was one of the permanent judges in the reality television show AIRTEL Super Singer on Vijay TV in seasons and 2008 Idea Star Singer on Asianet. Unnikrishnan is also becoming known for his experimental work. In 2008, he presented a novel jazz concert in Thiruvananthapuram with the Eli Yamin Jazz Quartet and pianist Anil Srinivasan. He prefers singing classical songs over pop music. He is the recipient of many awards like Tamil Nadu's Kalaimamani, Nada Bhushanam, Isai Peroli, Yuva Kala Bharathi, Isayin Punnagai, Isai Selvam, Sangeetha Kalasarathy, Sangeetha Chakravarthy. In 2012, Unnikrishnan rendered a series of Devotional songs on Lord Ganesha, Lord Ayyappan, Lord Venkateswara, and Devi among others. The albums were produced by Gaananjali Recordings and were composed and released by Manachanallur Giridharan. The album titles include Ayyan Malai Engal Malai, Om Nava Sakthi Jaya Jaya Sakthi, Sabarimalai Va Charanam Solli Va, Vindhaigal Purindhai Nee En Vazhvile, and Uchi Pillaiyare Charanam. Notable among them is the Harivarasanam, part of the Ayyappa album and is the only other popular rendering after the famous K. J. Yesudas's.
Personal life
Unnikrishnan is married to Priya, a Bharathanatyam and Mohiniyattamdancer and a native of Kozhikode, Kerala. They were married on November 1994 and have 2 children – a son named Vasudev Krishna and a daughter named Uthara. Vasudev Krishna was born on 27 May 1997 and Uthara was born on 11 June 2004. Uthara won the National award for playback singing for her debut song "Azhagu" in the movie "Saivam". One notable fact is that both Unnikrishnan and Uthara received national awards for their debut songs. Vasudev is passionate about cricket and is a member of the Madras Cricket Club and Life Member of the Tamil Nadu Cricket Association.