M. Rajah was born to Manmadharaju and Lakshmamma. His father died when he was three months old and then the family moved to Renukapuram and Chennai. His tertiary education was at Pachaiyappa's College from where he graduated with a B.A. Degree. By this time, Rajah was an accomplished piano player and had won several prizes in singing competitions. He was well versed in Carnatic Music and Western Classical Music. During his University days, Rajah wrote, composed and sang two songs in his mother tongue, Telugu, with the instrumental support of the music director K. V. Mahadevan for HMV which were broadcast by All India Radio. Gemini Studios boss S. S. Vasan listened to these songs and, impressed, booked him for his next film, Samsaram (1951) with the approval of his music director, Emani Sankara Sastry, and also his good friend Kalki Krishnamurthy. By this time Rajah was also already recording songs for the films Rajambal with P. Leela and Kumaari with Jikki for music composers M. S. Gnanamani and K. V. Mahadevan respectively. Rajah, with instant popularity after the Samsaram songs came on the air, went on to sing in various languages, including Hindi and was the uncrowned prince of the South in the early and mid-1950s. He was equally successful in Telugu, Tamil, Malayalam and Kannada films. His first Telugu film was Adarsham in 1952. His first song in Malayalam was for film Lokaneethi (1952), music director being the composer V. Dakshinamoorthy. He sang for almost all the South Indian film music composers of the 1950s. A. M. Rajah was the first male playback singer from the South to have recorded songs for a Hindi film in Bombay for Bahut Din Huye in 1952. He also sang in few Sinhala films produced in Chennai and Sri Lanka with Jikki. Many of his solo songs and duets with all the leading female playback singers of that era were big hits. A. M. Rajah's debut as music composer was for the Telugu film Sobha 1958. He then composed music for Aadi Perukku (1962) directed by K. Shankar. Thus ended Rajah's active film career which witnessed a meteoric rise and then an abrupt end after just 10 years. All his films as music composer were musical hits with Kalyana Parisu and Then Nilavu joining the list of all-time greats. He married P. G. Krishnaveni (popularly known as Jikki), had four daughters and two sons. A. M. Rajah died on 7 April 1989 at the age of almost 60 in an unfortunate train accident when he tripped and fell into the tracks while boarding a moving train.