Janani Iyer was born in Chennai, Tamil Nadu, India into a Tamil family. Brought up in Chennai as well, she studied at D.A.V. School in Gopalapuram and later completed engineering in computer science at Saveetha Engineering College in Chennai.
After her studies, Janani Iyer ventured into modelling and appeared in over 150 regional television advertisements. However, she said, she always dreamt of becoming an actress, considering acting to be her “passion in life”. During her modelling career, she appeared in insignificant cameo roles in Thiru Thiru Thuru Thuru (2009) and Gautham Menon’s Vinnaithaandi Varuvaayaa (2010).
In early 2010, following the recommendation of director A. L. Vijay, Janani went to audition for director Bala, who was looking for a Tamil-speaking new face for the lead female character in his new film project, Avan Ivan. Upon seeing her audition, Bala signed her for the role. The comedy-drama film, which also starred Arya, Vishal Krishna and Madhu Shalini, featured Janani in the role of an innocent police constable. Her next release was Paagan, in which she was paired opposite Srikanth