Hamsika received her initial training in music from her father, a Carnatic musician and musicologist based in Mumbai. In 1995, Iyer participated in two Zee TV music shows, Close Up Antakshari and Sa Re Ga Ma. She was a finalist on Sa Re Ga Ma and was also invited to participate its 100th episode.
Vidhu Vinod Chopra's Eklavya: The Royal Guard in 2007 was her big break and her song Chanda Re – popularly known as The Moon Song – went on to become a hit that year.
Hamsika is the brand ambassador for international NGO – GOAN Shave, a children cancer charity.