Kim was born in Ahmednagar to an Indian father and a Japanese mother. She has 3 sisters. Kim did her schooling at
St. Joseph's Convent in Panchgani. She then returned to her hometown and joined a junior college. Of her college days, she said 'Having studied in a boarding school, where most of the girls were from aboard, living and studying in Ahmednagar came as a culture shock'. While in her twelfth standard, she decided to quit studies. Her niece used to study in Army Public School of Ahmednagar. As one of the famous faces of Ahmednagar college, she was offered many fashion shows and modeling.
In August 2011 it was revealed that Kim had secretly married a Kenyan businessman named Ali Punjani, who she had been dating for a few weeks. 
On a trip to Mumbai, she auditioned for Close-Up toothpaste and was selected. She then appeared in Sunsilk, Pepsi, Tata Safari, Ponds, Fair & Lovely, Clean-n-Clear and Liril advertisements. She is also the brand ambassador of Olay in
Sharma caught the eye of producer Aditya Chopra who signed her for his next directorial venture titled Mohabbatein. The film also marked the launch of five other newcomers-Uday Chopra, Jugal Hansraj, Jimmy Shergill, Shamita Shetty and Preeti Jhangiani. Mohabbatein also starred superstars Amitabh Bachchan, Shah Rukh Khan and Aishwarya Rai Bachchan. It was a huge hit and started Kim's career in Bollywood.