Keishing participated in the Indian freedom struggle; including attending meetings as a student, during 1945-47. He was a member of the
Socialist Party of India, the Indian delegation to the
Asian Socialist Conference held in
Rangoon (Myanmar), the
Indian National Congress, the Indian delegation led by the late Shri
Yashwantrao Chavan to the 35th General Session of the
UN held in U.S. in 1975, the Indian delegation to attend the 51st Commonwealth Parliamentary Conference held at Sheraton,
Fiji, 2005 and Tenth Finance Commission. He was the founding headmaster of the first high school in the district of
Ukhrul, a founding member and honorary headmaster of
Phungyar High School, and a founding member of a high school in
Kamjong and
Kasom Khullen. He served as Chairman to the Eastern Border Development Authority and Barak Development Board; and helped to set up the Foundation for Management of Tribal Areas (MATA) in 1998, the Fresh Ginger Oil Processing Pilot Project with technology developed by the
NIIST,
Trivandrum in 1998 and the Fruit Processing Unit with technology developed by the
CFTRI,
Mysore. In 1952, Keishing was elected to the first
Lok Sabha representing the Socialist Party. During his second term in the Lok Sabha, he informed Prime Minister
Jawaharlal Nehru that he wanted to join the Indian National Congress and remained with the party until his death. He first entered Manipur State's
Vidhan Sabha in 1972, winning
Phungyar seat, and represented the seat for 30 years, winning the election 7 times. In 2002, he lost in the assembly polls. His son, Victor Keishing, reclaimed the seat a few years later. After his defeat in the state polls in 2002, Rishang Keishing moved to Delhi, representing the state in
Rajya Sabha for two terms, 2002 to 2008, and 2008 and 2014. In 2007 he became the country's oldest parliamentarian. He retired from Rajya Sabha in 2014, at the age of 93. Keishing, along with D. Athuido, a former Member of the Legislative Assembly, was expelled from the Manipur Congress for six years in May 1968 for signing a memorandum to the Prime Minister of India which suggested that the Naga-inhabited areas of Manipur should be merged with
Nagaland. In August 1972, he spearheaded an agreement between then United Naga Integration Council and the ruling Indian National Congress which recognised the vision of a Greater Nagalim, a region that would integrate Nagaland and the Naga-populated districts of Manipur under one administration. In 2014, Keishing declared that he would not contest the Rajya Sabha elections after serving two consecutive terms. He said, "I am not interested to continue now." ==Personal life==