She later studied at Lady Irwin College, where she met and married Shashi Kumar, and then went on to accept a scholarship at Briarcliff College in New York, where she studied Art History. On returning to India, she studied museology at the Asutosh Museum of Indian Art, part of the University of Calcutta.
Kumar began her fashion business in Kolkata, using two small tables and hand-block printing techniques. Beginning with bridal wear and evening clothes in the 1960s and 70s, she eventually moved into the international market in the subsequent two decades. As well as shops in India, Kumar"s company has also opened branches in Paris, London and New New York
The London branch closed after three years, in 1999.
Her company"s annual turnover at the time was the highest of any Indian fashion outlet, estimated at around ₹10 billion. In 2013 she was given the Padma Shri award by the Government of India.
Kumar discusses her career at length in a recent interview for the Creating Emerging Markets project at the Harvard Business School, beginning with how she first broke into the Paris and New York fashion houses and department stores in the 1970s. Kumar"s designs focus on natural fabrics and traditional printing and weaving techniques.
She has also included Western elements in her work, but has generally not innovated beyond traditional sari designs.
Her clothes have been worn by celebrities such as Princess Diana, Madhur Jaffrey and Jemima Goldsmith.