Tanuja was born in a Marathi family to filmmaker Kumarsen Samarth and actress Shobhna Samarth. She has three sisters, including actress Nutan and one brother. Her grandmother, Rattan Bai, and aunt Nalini Jaywant were also actresses. Tanuja's parents parted amicably while she was still a child, and Shobhana became linked to actor Motilal. Shobhana produced debut films for Tanuja and her older sister, Nutan. Her two other sisters are, Chatura, an artist, and Reshma, and brother is, Jaideep, neither of whom took to acting.
Tanuja married filmmaker Shomu Mukherjee in 1973. The couple has two daughters, actresses as are Tanuja's daughters Kajol and Tanisha. Kajol is married to actor Ajay Devgan. Shomu died on 10 April 2008 from a heart attack aged 64. Filmmakers Joy, Deb and Ram are her brothers-in-law. She is the aunt of actors Mohnish Behl, Rani, and Sharbani, and director Ayan Mukherjee.
She started her film career with her older sister Nutan in Hamari Beti (1950) as Baby Tanuja. As an adult, she debuted in the film Chhabili (1960) which was directed by her mother and had her sister, Nutan, in the lead. The film that truly marked her transition into adult heroine came with Hamari Yaad Aayegi (1961), directed by Kidar Sharma, who had earlier discovered Raj Kapoor, Madhubala and Geeta Bali.
One of her early films, noticeable for her acting, was Baharen Phir Bhi Aayengi (1966), directed by Shaheed Latif. Incidentally it was Guru Dutt team's last offering, especially visible in the song, "Woh Hanske Mile Humse" (believed to have been picturized while Guru Dutt was still alive) who worked hard to help her "tone down" her performance. The result was that the natural, spontaneous performer gave a highly restrained performance which became the highlight of the film — as well of her career — as she moved to lead roles soon after. Tanuja had an important supporting role in the hit film, Jewel Thief. Her next big film was with Jeetendra, Jeene Ki Raah (1969), an immediate and surprise hit. In the same year, Tanuja won the Best Supporting Actress at Filmfare for Paisa Ya Pyar. After the success of Haathi Mere Saathi (1971), she acted in Door Ka Raahi, Mere jeevan Saathi, Do Chor and Ek Baar Muskara Do (1972), Kaam Chor, Yaarana, Khuddar, and Masoom. Some of the other films she has acted in are Pavitra Paapi, Bhoot Bangla, and Anubhav. Some of her Marathi films are 'Zaakol', 'Unad Maina' and Pitruroon.
During the mid 1960s, Tanuja started a parallel career in Bengali movies in Kolkata starting with Deya Neya (1963) where she was paired opposite Uttam Kumar. She followed it up with Anthony-Firingee (1967) and Rajkumari (1970). Tanuja had on-screen chemistry with Soumitra Chatterjee with whom she made some films like Teen Bhuvaner Parey (1969) and Prothom Kadam Phool. Tanuja spoke her own lines in these Bengali films.
Afterward, Tanuja retired from films for a number of years but came back when her marriage ended. She was now offered supporting roles often starring former heroes. Her Pyar Ki Kahani hero Amitabh Bachchan had to call her "bhabhi" (sister-in-law) in Khuddar (1982). She also played a supporting role in Raj Kapoor's Prem Rog (1982).
She then appeared in films such as Saathiya (2002), Rules: Pyaar Ka Superhit Formula (2003), and Khakee (2003) as a supporting actress. In 2008, Tanuja starred as a judge along with her daughter, Kajol, and son-in-law, Ajay Devgan on Zee TV's family dance series Rock-N-Roll Family. In 2013, Tanuja played a widow in Marathi film Pitruroon made by Nitish Bharadwaj. For her role as widow Tanuja has tonsured her head to make her character look authentic.1964: Bengal Film Journalists Association Awards - Best Supporting Actress (Hindi), Benazir (1964)1968 - Filmfare nomination as Best Supporting Actress for Jewel Thief1970 - Filmfare Best Supporting Actress Award for Paisa ya Pyar2013 - Best Actress Award for Marathi Movie Pitur Roon at the 20th Life OK Screen Awards2014 - Lifetime Achievement Honour at Apsara Film & Television Producers Guild Award2014 - Filmfare Lifetime Achievement Award