After completing her reign, Sen went on to pursue Bollywood. She started her career with the Hindi film, Dastak. She rose to stardom with the Tamil musical Ratchagan opposite Nagarjuna; later, she attained commercial and critical recognition for her roles in Sirf Tum (1999) and the comedy Biwi No.1 (1999). The latter earned her the Filmfare Best Supporting Actress Award. She has also acted in commercially successful films such as Aankhen (2002), Main Hoon Na (2004) – her biggest commercial success so far — and Maine Pyaar Kyun Kiya? (2005). She received critical acclaim for her female-oriented roles in films such as Filhaal... (2002), Samay: When Time Strikes (2003), Chingaari (2005), Zindaggi Rocks (2006), Aag (2007) and others.
Sen was born into a Bengali family in Hyderabad. Her parents are Shuber Sen, a former Indian Air Force Wing Commander, and Subhra Sen, a jewelry designer and owner of a Dubai-based store. She has two siblings, a sister named Neelam and a brother named Rajeev.
She has attended Air Force Golden Jubilee Institute in New Delhi and St. Ann's High School in Secunderabad, but did not pursue higher education.
Sen adopted a baby girl in 2000 and a second girl in 2010.
In 1994, as a teenager, Sen won the title of Femina Miss India. Sen then won the 1994 Miss Universe Pageant, held in Manila, Philippines, representing India.
At the Miss Universe contest, Sen ranked third overall in the preliminaries, right behind preliminary winner Miss Colombia Carolina Gómez, and Miss Greece Rea Totounzi. Sen went on to place second, fifth and third in the forthcoming rounds, and finally winning the overall competition. After Femina Miss India relinquished the rights to choose the Indian representative to Miss Universe, Sen's project I Am She – Miss Universe India, which ran from 2010 - 2012, took over. From 2013 onward, Femina was awarded the contract back once again.
As a celebration of 65th Miss Universe, 23 years after winning the pageant, she returned to Manila, Philippines, in January 2017, as one of the judges of the Miss Universe 2016 beauty pageant. The pagent took place at the Mall of Asia Arena, Pasay, Metro Manila, Philippines on January 30, 2017. Joining her as judges were Cynthia Bailey, Mickey Boardman, Francine LaFrak, Miss Universe 2011 Leila Lopes, and Miss Universe 1993 Dayanara Torres.
After her reign as Miss Universe, Sushmita became an actress. Her first film, Dastak was in 1996, in which she played the victim of a stalker played by Sharad Kapoor. Mukul Dev starred as the lead actor. She then starred in the 1997 Tamil, action film Ratchagan. Two years later her appearance as Rupali in David Dhawan's movie Biwi No.1 won her the Filmfare Best Supporting Actress Award in 1999. Biwi No.1 was the second highest-grossing movie of 1999. The same year, she was also nominated for her role in Sirf Tum in the same category. Following her dance song in Fiza known as 'Mehboob Mere', she tried to make a niche for her career in the Indian film cinema.
She received critical acclaim and box office success for film Aankhen starring opposite Arjun Rampal. The film co-starred Amitabh Bachchan, Akshay Kumar, Aditya Pancholi and Paresh Rawal. So far, her biggest hit has been the 2004 movie Main Hoon Na, in which she starred as Shahrukh Khan's love interest. The film grossed a total of Rs 330,000,000 and was the second best selling movie of that year. Later, Sushmita played a lawyer in Main Aisa Hi Hoon opposite Ajay Devgan. In 2005, she also starred in a remake of Cactus Flower, called Maine Pyaar Kyun Kiya?: Sen played the lead opposite Salman Khan and Katrina Kaif.
Sushmita plays the role of a successful supermodel called Shimmer in Dulha Mil Gaya; the film was a moderate success that year. In 2015, she did a Bengali film Nirbaak.
Geo Asia spa award