Koel completed her school level education from the Modern High School for Girls in Kolkata and graduation from Gokhale Memorial Girls' College in Kolkata. After completion of her graduation, she made her cinematic debut with the Bengali film Nater Guru in 2003. She was cast opposite actor Jeet and movie was a smash hit at the box office.
Though some of her next films flopped at the box-office but her flick Bandhan where she was again cast opposite Jeet became a blockbuster hit and made her an overnight star of Bengali cinema. After which, she has been highly active and has worked in around 50 Bengali movies. Her last movie was Besh Korechi Prem Korechi which was released in 2015.
Besides films, she has also been active on the small screen as well. She also served as a judge of Bengali version of Jhalak Dikhlaaja. Her most popular television series was Bojhena Se Bojhena. Arguably she has been one of the biggest stars of Bengali cinema for over a decade.
She has also endorsed various products such as Fair & Lovely, Vaseline, TVS Motor Company and Panasonic among others.