The first time Manorama stood before the camera was for a Sinhalese film "Sukumali" in 1947, in which she played the heroine's friend. Her dance master Suryakala recommended her to the director Masthaan to play the role. She has acted predominantly in Tamil films since 1958, but also acted in Telugu, Hindi, Malayalam and Kannada movies as well. Her on-screen pair with Tangavelu was appreciated in the film "Vallvanakku Vallavan" in 1965. Her on-screen pair with Nagesh was very popular in 1960–69 and then with Cho in the 1970s and 80s and later with Thengai Srinivasan, Venniradai Moorthy, and Surali Rajan in the 70s and 80s. She had done playback singing for 300 songs, mostly pictured on herself, in Tamil films. The first song that she sang was in a film called "Magale Un Samathu", composed by G. K. Venkatesh and this opportunity she got due to the film's producer P.A. Kumar. She has sung a classical-based song with TM Sounderajan in the film "Dharshinam" (1970), where she was paired with Cho. Manorama sang a song with L.R. Eswari named "Thaatha thaatha pidi kudu". Her career's biggest hit song sung by herself was Vaa Vaathiyaare Uttaande composed by music director V. Kumar for the film "Bommalattam", which was picturised on her and Cho. She also sang for M. S. Viswanathan and A. R. Rahman.