Mumtaz was born to Abdul Saleem Askari and Shadi Habib Agha in Bombay, India, on 31 July 1947. She entered Hindi cinema at age 12,
She started as an extra in films in the early 1960s. She accepted small roles in big films like Mujhe Jeene Do and big roles in small budgeted stunt films like Boxer, Samson, Tarzan, and King Kong. In the 1960s, she starred in as many as 16 action films with freestyle wrestler Dara Singh and was labelled as a stunt film heroine.
She first gained attention in a supporting role as a vamp in the A grade color hit film Mere Sanam (1965). The memorable sexy song "Yeh Hai Reshmi Zulphon Ka Andhera" was picturized on her. The success of the film led to another sizzling song "Aye dushman jaan" in another big-budget film Patthar Ke Sanam. Finally, she gained major attention when she played one of Dilip Kumar's leading ladies in Ram Aur Shyam (1967). The film became one of the top hits of the year, and she received her first Filmfare nomination as Best Supporting Actress. Suddenly, Mumtaz was flooded with offers but not for major leading lady roles. She supported Sharmila Tagore in several films in the late 1960s, such as for Saawan Ki Ghata, Yeh Raat Phir Na Aayegi, and Mere Humdum Mere Dost. She had a memorable song and dance number "Aaj Kal Tere Mere" with her co-star Shammi Kapoor in the hit film Brahmachari (1968).
It took Raj Khosla's blockbuster Do Raaste (1969) starring Rajesh Khanna to finally make Mumtaz a full-fledged star. Oddly, it was an inconsequential girlfriend role, but director Khosla, so good at picturizing songs, filmed four hit songs on Mumtaz. The film made her hugely popular, and she acknowledged that, even though she had a small role, it was still one of her favorite films. When earlier, she had played a small role as Rajendra Kumar's sister in Gehra Daag, now she was elevated to playing his leading lady in Tangewala. Shashi Kapoor who had earlier refused to work with her in Saccha Jootha because she was a "stunt film heroine" now wanted her to be his heroine in Chor Machaye Shor.
Mumtaz acted in over a hundred films in a career that spanned just 12 years. She won the Filmfare Best Actress Award for one of her favorite films Khilona in 1970, and she was "very happy that the audience accepted her in an emotional role." Mumtaz starred in many movies with Feroz Khan and had other popular pairings with Jeetendra and Rajesh Khanna. She has also acted with Dharmendra, Sanjeev Kumar and other top heroes of her era. She was proud of her work in her other favorite films Tere Mere Sapne for director Vijay Anand, as well as Roop Tera Mastana, Aap Ki Kasam, and Aaina.
She quit acting after her appearance in Aaina (1977) which was a flop, even though it had co-starred Rajesh Khanna and was directed by famous director Kailasam Balachander. After that, she left films for marriage to a millionaire and only returned for one final appearance 12 years later in the 1989 film Aandhiyan, which flopped and she turned down other film offers. In 1996 she received the Filmfare Lifetime Achievement Award.
In June 2008, she was honored for her "Achievement in Indian Cinema" by the International Indian Film Academy (IIFA) in Bangkok.
Mumtaz has featured recently in UniGlobe Entertainment's cancer docudrama 1 a Minute with a number of international stars.