Sanghamitra's formal education began at 'Adi Mahakali Pathsala', a distinguished school in North Kolkata founded by Mataji Gangabai.
She was also an accomplished classical dancer who received her training from the likes of Thankomani Kutti (Bharatnatyam), Nataraj Parimal Krishna, and Bela Arnab (Kaththak), and Ramgopal Bhattacharya (Creative Dance).
While she was a student of University of Calcutta, in 1979, Sanghamitra was selected by Uttam Kumar, the legendary actor, who cast her in his last directorial venture, 'Kalankini Kankabati' which was released in August 1981.
The song 'Bedhechi Veena Gaan Shonabo Tomaye' set to tune by Rahul Dev Burman, sung by the renowned classical singer Begum Parveen Sultana and picturized on Sanghamitra had gained immense popularity.
In 1981, Sanghamitra was approached by Umanath Bhattacharya to play a pivotal role in his directorial venture, Ashililatar Daye.
Some of her memorable dramas include Ghar Jamai, Aparajita, Swargo Narak, Mallika, Sujata, Golok-Dhanda, Samrat O Sundari, etc.
In the small screen, she was seen in serials like Peter Uncle, Manorama Cabin, Seemarekha, Ogo Priyotama, Asha, Katha, Nishkriti, Bordidi, Luckochuri and Tritiya Pandav.
Among the notable films she acted in this decade were: Proshno, Surer Bhubone, Abhimanyu, Mahabharati, Rupoban Kanya, Kancher Prithibi, Thikana, Laho Pronam, Shesh Pratiksha, Atmaja, Anutap, Prathama, Dristhi, Karna, Tarini Tara Ma, Bohurupa, Tomar Amar Prem, Ganga, Ami Je Tomari, Amie Sei Meye, Kali Amar Ma, Lathi, Loafer, Chowdhury Paribar, Sedin Chaitra Mash, Mittir Barir Chhoto Bou, Bishnu Narayan, Kulangar, Tumi Ele Tai, etc.
In the decade and a half that followed, she acted in more than a hundred films which include titles like , Shasti, Pita Swarga Pita Dharma, Streer Maryada, Sharbari, Ke Apon Ke Por, Premi, Prem Korechi Besh Korechi, Shubhodrishti, Devi, Bazi, Tekka, Chakra, Shakal Sandhya, Adhikar, Ranangan, Shudhu Tomar Jonyo, Antaratamo, Dhaki, Jodi Kagoje Lekho Naam, Ekbar Bolo Bhalobashi, Ekbar Bolo Bhalobashi, Simanto Periye, Blackmail, Surya—The King, Aalo Chaya, Achena Bondhutto, etc.
In her acting career, Sanghamitra had worked under the direction of legends like Tapan Sinha, Tarun Mazumdar, Utpal Dutta, Madhabi Mukherjee, Nabyendu Chatterjee, Dilip Roy, Dinen Gupta as well as with eminent directors of commercial movies like Anjan Choudhury, Prabhat Roy, Swapan Saha, Haranath Chakraborty, Sujit Guha, Ravi Kinagi, etc.
As a mark of recognition of her acting skills and literary contributions in Bengali literature, she was honored with the B. C. Roy Memorial Award in 2008.