He attended the London Academy of Music and Dramatic Art in British repertory theatre.
He is known for his critically acclaimed performances in the films Gandhi, Mississippi Masala, Not Without My Daughter, My Beautiful Laundrette, Indiana Jones and the Temple of Doom, Such a Long Journey, and Street Fighter: The Movie. He is the brother of retired Indian diplomat Aftab Seth. He was educated at The Doon School, then furthered his education doing graduate studies in History at Street Stephen"s College.
There, he honed his theatrical skills at the Shakespeare Society, before moving to England for further training.
Seth"s first break came in Peter Brook"s production of A Midsummer Night"s Dream, which toured in 1972. Seth entered feature films in Richard Lester"s Juggernaut (1974), but because subsequent filmmakers only wanted Seth for ethnic roles, his career abruptly stalled.
Discouraged, he abandoned acting and returned to India, where he worked as an editor and journalist until the early 1980s, when Richard Attenborough asked Seth to play Jawaharlal Nehru in Gandhi (1982). Seth was nominated for the British Academy of Film and Television Arts Award for Best Actor in a Supporting Role for his performance in the film.
Seth also played Jawaharlal Nehru in Bharat Ek Khoj, a 53 episode series on Doordarshan in 1988.
Also in 1982, Seth played Indian author Victor Mehta in David Hare"s biographical play, A Map of the World, which toured for several years in Australia, London, and New New York After the release of the multi-award-winning movie Gandhi (1982), Seth was much in demand, and when A Map of the World"s Broadway run finished, his movie career took official His work in 1984 included major roles in Indiana Jones and the Temple of Doom and David Lean"s A Passage to India.
Following that he played a lead in My Beautiful Laundrette (1985), and he played Pancks in Little Dorrit (1988).
Seth"s film credits in the 1990s included roles in Not Without My Daughter (1991), Mississippi Masala (1991), Street Fighter (1994), and Harish Saluja"s The Journey (1997). In 2001, Seth appeared in Monsoon Wedding, and he has continued working steadily in British and American films.
In 2003 he played the lead in the American film Cosmopolitan, which was broadcast nationally on Public Broadcasting Service. He also recently returned to mainstream Indian cinema with his role in the 2012 film, Ek Tha Tiger.