Tanisha comes from a prominent film industry family, which has been working in Bollywood since the 1940s. Her relatives include paternal grandfather Sashadhar Mukherjee, uncles Joy Mukherjee and Deb Mukherjee, great-grandmother Rattan Bai, grandmother Shobhna Samarth and aunt Nutan. Her father is Somu Mukherjee and her mother is actress Tanuja. Her sister is popular actress Kajol whilst her cousins are Mohnish Behl, Sharbani Mukherjee and Rani Mukerjee.
Tanisha's paternal grandfather was a film director and producer who had left a great achievement in the Bombay film industry and was regarded as a stalwart. His wife Satirani Devi, Tanisha's grandmother was the sister of three great film personality Ashok Kumar, Anoop Kumar and Kishore Kumar.
She made her debut with Sssshhh opposite Dino Morea. The film did not do well. Following releases didn't do very well at the box office either. Tanisha's first hit film was Ram Gopal Varma's Sarkar, which starred film legend Amitabh Bachchan and his son Abhishek Bachchan. Recently, she played the female lead character of Nikkita "Nikki" Bakshi in Neal N Nikki, which failed to make an impact at the box office.