Ousephachan was born to Mechery Louis and Mathiri Paliakkara on 13 September 1955 in Ollur, Thrissur, Kerala, India.He completed his formal education from Saint Thomas College, Thrissur. He was interested in music and by the time he finished his formal education, he had become an expert violinist. He started his music career as violinist in some music troupes including Voice of Trichur. Later he got the chance to be the violinist in concerts of renowned playback singer Madhuri. He later became the violinist under music director Paravoor Devarajan master.Then he moved to Madras, Tamil Nadu where most of the recording works of Malayalam films were done. His first work in the film industry was the film Eenam, for which he set the background score. He also composed additional background music for the film Aaravam (1979) in which he also played the role of a fiddle player, however Kathodu Kathoram (1985), directed by Bharathan is considered as his debut. Ouseppachan's work was noted for the film and three songs from the film became super hits. These songs were noted also for the immense use of violin. This may be attributed to the facts that Ousephachan himself is a violinist and that the protagonist of the film played by Mammootty is also a violinist.Ousephachan then went on to compose music for over 120 films. He also composed songs for the non-commercial Hindi film Freaky Chakra, directed by V.K. Prakash and background scores for various other Hindi films, notably directed by Priyadarshan. His non-film songs include popular albums like Onapoothalam, Vasanthageetangal and many Christian devotional songs.Aside from music direction, he had taken up a spot as a judge for Asianet's Idea Star Singer 2008 and also as a judge for Kairali TV's Gandharva Sangeetham 2012.He got his first state award in 1987 for the movie Unnikale Oru Kadha Parayam. His first national award was for ace Director Shyamaprasad's Ore Kadal in 2007. All the songs in this film are composed in Shubhapantuvarali raga but all have their identity. Apparently, it is a challenge given to Ouseppachan by the director and he took up the challenge. His recent notable films are Ayalum Njanum Thammil, Nadan. For Nadan, he recreated the classical drama songs from the classical K.P.A.C era. He received a state award for this film for Best Music Director. Many of the famous musicians were his disciples. This includes A.R.Rahman, Vidyasagar, Harris Jayaraj etc. Composer Gopi Sunder was his assistant and the violin bit from the famous song "appangalembadum" from Ustad Hotel is played by Ousepachan.