Manisha was born in the Nepali Koirala family on August 16, 1970. Her dad, B.P. Koirala, was Nepal's Prime Minister before her birth, while two of her paternal grandfather's brothers, Girja Prasad Koirala, and M.P. Koirala were also Nepali Prime Ministers during the 1990s. She studied at Army Public School, Dhaula Kuan, New Delhi and Vasant Kanya Mahavidhyalaya Varanasi. She lived with her grandmother in Varanasi during her studies. Her ambition was to be a doctor, but a lucky chance with modelling helped her get a career in Bollywood. She has obtained a Diploma in Film Making from New York, U.S.A., and is a member of the Independent Film-Makers Society. She is also the goodwill ambassador on U.N.F.P.A.. She is actively involved in bettering the status of women, women's rights, prevention of violence against women, as well as in the active prevention human trafficking, especially Nepali women, who are abducted and sold as prostitutes. She is well versed in the Bharatnatyam and Manipuri dance forms.