Saswata started his career with a Hindi serial directed by Saibal Mitra, based on Samaresh Majumdar's Kaalpurush. He gained popularity by portraying the character of Topshe in a television series directed by Sandip Ray. His breakthrough role came in Sujoy Ghosh's 2012 blockbuster Hindi film, Kahaani (2012), where he played a simple looking scary contract killer Bob Biswas. The nation went berserk with his portrayal of the villain and comparisons with the iconic Bolly-baddies 'Mogambo' and 'Gabbar Singh' were also drawn. His most notable work includes the role of TV show creator Abhijit Ganguly in the breakout hit thriller Network (2019) directed by Saptaswa Basu