Sen was born into a Bengali Baidya family in Hyderabad. Her parents are Shubeer 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.

Femina Miss India

In 1994, as a teenager, Sen participated in the Femina Miss India contest. She won the title 'Femina Miss India Universe', earning the right to compete at the Miss Universe 1994 contest.

Miss Universe

At the Miss Universe contest, Sen ranked third overall in the preliminaries, behind Miss Colombia Carolina Gómez and Miss Greece Rea Totounzi. Sen went on to place second, fifth and third in the subsequent rounds and finally won the title and crown of Miss Universe 1994. She was the first Indian to win the title.^[15]

After the Times Group relinquished the rights to choose the Indian representative to Miss Universe, Sen's project, I Am She – Miss Universe India, took over. It ran for three years (from 2010 to 2012). In 2013, Femina was awarded the contract back.^[16]

Miss Universe 2016

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.^[17] The pageant 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.^[18]

1990s

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.^[19] The same year, she was also nominated for her role in Sirf Tum in the same category. She appeared in a dance song in the movie Fiza, in the year 2000.

2000s

She received critical acclaim and box office success for the 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.^[20] 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. She also played the leading role in Karma Aur Holi.

2010s

In 2010, Sushmita played the role of a successful supermodel called Shimmer in Dulha Mil Gaya; the film was a moderate success that year.^[21] She additionally appeared in the action-comedy film No Problem the same year.^[22] In 2015, she starred in a Bengali drama film titled Nirbaak.^[23] In Sushmita's career, this was her first film in Bengali language.^[24]

Sen adopted a baby girl in 2000 and a second girl in 2010.^[3][25]