Santhosh Narayanan did his schooling in RSK Higher Secondary School, Tiruchirappalli and college in J. J. College of Engineering and Technology, Tiruchirapalli. After completing his education, he briefly worked as an assistant to composer A. R. Rahman. He worked as a recording engineer, before beginning to produce independent music and compose background score for films. He scored the music including two songs for the acclaimed short film Advaitham, and produced the score for the Telugu thriller film Nenu Meeku Telusa along with another Rahman protege, Sakti. He made his debut as an independent music director in the 2012 Tamil film Attakathi directed by Pa. Ranjith. Following Attakathi, he composed the music for the films Uyir Mozhi and Pizza, the directorial debuts of Raja and Karthik Subbaraj, respectively. He also won accolades that year: the Jaya TV 2012 award for Sensational Debutant Music Director for Attakathi, and the Big Tamil Melody Award for Best Debut Music director for Pizza. He had four soundtrack releases that year, the first being the album to the romantic drama Cuckoo. The next release was Karthik Subbaraj's second directorial, Jigarthanda. The soundtrack and score featured a melange and fusion of several genres, including Gangsta rap, folk, electro. After Jigarthanda, he worked on the action-drama film Madras. In 2015, he worked on 36 Vayadhinile, the Tamil remake of the Malayalam film How Old Are You. His on-going projects are Kabali, Server Sundaram and Vijay 60.