S. Janaki was born in Pallapatla, Repalle village, Guntur District of Andhra Pradesh. Janaki showed interest in music at a tender age and started singing at the age of three. She started learning music from a nadaswaram vidwan, Sree Paidiswamy. She moved to Chennai on the advice of her uncle Dr. Chandrashekar and joined as a singer in AVM Studio and started her career with Tamil films in 1957 in the film 'Vidhiyin Vilayattu' under the music director T. Chalapati Rao. Later, she got a chance in a Telugu film MLA.