In the initial stages Sushma Seth was a theater worker and then she shifted to films. She got the opportunity to work with some of the very renowned directors including D.R. Ankur, Manish Joshi, Manish Bajaj, Chander Shekhar Sharma and Bismil. She had also starred in some of the blockbusters of the Hindi Film Industry such as 'Prem Rog', 'Chandni', 'RamTeri Ganga Maili', 'Kabhi Khushi Kabhi Gham' and 'Kal Ho Na Ho'. Her acting prowess in the movie titled 'Tawaif' by B.R. Chopra made her received a nomination for Filmfare Best Supporting Actress Award. She had essayed the role of a mother and grandmother to almost all the superstars of Bollywood including Rishi Kapoor, Shah Rukh Khan, Akshay Kumar, Preity Zinta, Anil Kapoor and others.
Besides creating a special place the Bollywood Film Industry Sushma Seth also appeared in host of television series. She was fortunate enough to work with eminent theater directors like Ram Gopal Bajaj and Manish Joshi Bismil. She has also appeared in several other tele soaps like 'Staying On' where she played the role of Codcod Menektra, the character of 'Dadi' in 'HumLog' and 'Dadiji' in 'Dekh Bhai Dekh'. She also proved her mettle in the art of acting by playing the role of 'Ammi' in 'Amma and Family' and the character of grandmother in 'Millie'. This brilliant artiste has created magic on stage, television and films with her skills. At present she is very much preoccupied with her work with a non-government organization called Arpana, which works for people evicted from the resettle colonies in South Delhi and now settled on Mathura Road. Her work is to teach the children drama and music and make them better persons. She is also working with other organization for awareness about AIDS, family planning and teaching various skills to teenagers. Her fans are proud of what she has achieved so far in her acting career and hopes that she goes some more miles before she finally ends.