Janaki's first song was in Tamil for the film Vidhiyin Vilayattu, recorded on April 4, 1957, and was a pathos song under the music direction of Sri. T. Chalapathi Rao. Strangely enough, the film never came out. About the film never getting released, Janaki playfully remarks that “Vidhi” indeed “Vilayadithu.” The very next day, she sang her very first Telugu song, “Nee Aasa Adiyaasa Chejaare Manipoosa Brathukantaa Amavaasa Lambaadolla Ramdaasa…,” for the film M.L.A., produced and directed by Sri Tilak. It was a pathos again, sung as a duet with Late Ghantasala Venkateswara Rao, which is remembered even today as one of the classics of Telugu film music. The song was penned by Sri. Arudra, and was sung under the music direction of Sri. Pendyala Nageswara Rao, Even her first Sinhalese song was a pathos recorded at AVM.

Janaki became sensational with her first experimental song (light classical), "Singaravelane Deva…" in 1958, under the music direction of Late S. M. Subbaiah Naidu, for the Tamil film Konjum Salangai. In the song, her voice competes with the Nadaswaram played by Late Karaikuruchi Arunachalam. The music director tested so many others’ voices to suit the notes played on Nadaswaram, as demanded by the scene, and finally chose Janaki. This song was appreciated and applauded by one and all in the South and also in the North and brought her laurels. She sang the Telugu version of this song, "Nee Leela Padeda Deva…" in the film Muripinche Muvvalu. Subsequently in 1961, Pendyala gave her a break with a solo song “Neeli Meghaalalo Gaali Kerataalalo Neevu Paade Paata…” in the film Baavaamaradallu” in the year 1961. The song won her critical acclaim from many music directors, and helped her get more chances to sing good songs.

Two years after she made a name for herself with the song "Singaravelane Deva…,” Janaki debuted in Malayalam films. Her first Malayalam song, incidentally, a pathos too, was for the film Minnunnathellam Ponnalla, and was recorded at AVM. Pronouncing Malayalam words was a big challenge for her. But she worked hard on the language, under the guidance of music composers and lyricists, and managed to speak it clearly. A fan of hers, Leela Chacko, used to call her up frequently, sometimes even in the wee hours. Janaki remembers that Leela became one of her good friends, and that speaking to her, Janaki’s Malayalam improved.

Comprehending her work in the industry for more than four decades, she has sung thousands of songs for almost five generations of heroines. She sang several unforgettable songs with the association of the maestros of music. She even rendered thousands of songs in Kannada leaving a lasting impression in the hearts of Kannada fans. There is one song that Janaki remembers as a particularly difficult one to sing: “It was in a Kannada movie, and was composed in two different ragams. The lyrics were like a tongue twister…” she recalls.