He was born on 10 November 1934 at Allahabad, Uttar Pradesh to Pandit Harish Chandra Tripathi and Smt. Shiva Devi. Keshari nath Tripathi is married to Sudha Tripathi and has three children, the eldest being Ms. Namita Tripathi then Mr. Neeraj Tripathi and then Mrs. Nidhi Ojha. His son is an advocate at the Allahabad High Court. Mr. Tripathi, a person who is constantly involved in the nations politics has not involved his children in such matters. His home town is Allahabad but at the moment resides at the Raj Bhavan of West Bengal.
He was a member of the Uttar Pradesh legislative assembly five times viz.1977-1980, 1989-1991,1991-1992,1993-1995, 1996-2002 and 2002-2007.He served as the Speaker of the UP Legislative Assembly from 1991-1993, 1997 to 2002 and from May 2002 to March 2004.He also held the position of Cabinet Minister, Institutional finance and Sales Tax in U.P. during the Janata Party regime from 1977-1979. He is also only Minister nominated 3 times as the Honorable Speaker of Vidhan Sabha.. On July 14, 2014 he was named as the next Governor of West Bengal.
He practiced as a Senior Advocate at Allahabad High Court. He is also an author and a poet and has published several books. His chief literary works are two anthologies called 'Manonukriti' and 'Aayu Pankh. On the professional side, his commentary on The Representation of People Act, 1951 is still widely esteemed. Aside from that he has written many other books not only in Hindi but also in English. He is also a part of the Hindi poets gathering that takes place both in India and in Abroad.