In any case, her career progressed successfully. In 1972, she moved to Delhi High Court, where she dealt with original civil petitions, criminal matters, company petitions, revisions and appeals.
Then, after serving on a panel of lawyers for the West Bengal government in the Supreme Court, she was designated as a senior advocate by the Supreme Court in 1977. In 1978, Seth became a Judge of the Delhi High Court, becoming the first woman to do so.