Born and brought up in Mumbai hailing from an educated Sindhi family. Sangeeta did her schooling from Mount Mary’s Convent High School and her college from M.M.K in Bandra, Mumbai.

Sangeeta started her modelling career at the tender age of 16 and signed a huge modelling contract with Dettol Soap and then went on to do many commercials and she became a household name with ads like Nirma, Vicco Turmeric, Cadbury’s Drinking Chocolate with Jackie Shroff, Fem Insto Bleach, Colgate, Pond’s Dreamflower Talc & Soap, Ramolene Suitings with ex-cricket Captain Mohammed Azharuddin and her famous ads of Graviera Suitings and Lakhani with actor Salman Khan. Sangeeta received her popular name ”Bijli” from her ramp walk days as she was often referred to as lightening on stage.

Sangeeta garnered the Beauty Queen title very early in life as she was first crowned as her School Queen followed by College Queen and then went on to win Campa Princess, Bombay Harbour, Jaycees Queen, Eagle Queen and then came Miss India Universe Title in 1980. Sangeeta represented India at the Miss Universe contest in Seoul, South Korea where she won the 1st Prize for Best National Costume award designed by her mother Poonam Bijlani.

Sangeeta started her Bollywood debut in 1988 with Qatil opposite Aditya Pancholi and then went on to do blockbusters like Tridev, Hathyar, Jurm, Yodha, Yugandhar, Izzat, Lakshman Rekha. She was spotted by director Rajiv Rai while on the ramp in a fashion show who convinced her to join Bollywood. She also did a bilingual in Hindi & Kannada opposite popular south star Vishnu Vardhan. She was nominated by the Filmfare Awards in the Best Supporting Actress category for Jurm opposite Vinod Khanna and was directed by Mahesh Bhatt and scripted by Salim Khan. She has worked with renowned directors like Mahesh Bhatt, Mukul Anand, J.P. Dutta, Rahul Rawail and N. Chandra

Sangeeta made her small-screen debut with Chandni - "a tale of power, revenge and love” in early 1996 opposite actor Shahbaz Khan. She also went on to produce popular comedy serial Hasna Mat with Kader Khan on Star Plus and Kinarey Milte Nahi on Zee TV.

Sangeeta and Salman Khan started dating each other in 1986 when they both were still modelling and their relationship lasted for 9 years. They eventually broke up. On 14 November 1996, Sangeeta married cricketer Mohammed Azharuddin at a star-studded reception at the Taj Mahal Hotel attended by the Bollywood and cricket fraternity in Mumbai. The marriage ended in a divorce in 2010 reportedly due to Azhar's alleged affair with badminton player Jwala Gutta, which was declined by the player.^[4][5]

In 2009 Bijlani campaigned actively for her husband Mohammed Azharuddin who was nominated from Moradabad for the Lok Sabha elections.