He was champion of backward classes and minorities. He appointed Mahajan Commission in Madhya Pradesh, much before the Mandal commission report was implemented by VP Singh Government. This commission recommended reservation for the backward communities in the government jobs. The OBC quota that he introduced in educational institutions in UPA-I drew controversy, but prepared Congress for an interface with electorally muscular backward castes whom the party missed during the Mandal Commission days.
He was a true and sincere friend of Indian Muslims too and did a lot for their betterment and upliftment as a member of Union cabinet.
However shrewd and a secularist Arjun Singh missed the biggest opportunity in the secular firmament of independent India at the time of the demolition of Babri mosque.
His biggest miss was the day after December 6, 1992 when he remained in the cabinet of Narasimha Rao while secularists were expecting him to resign. Rao was under fire for sleeping through the vandalism of secular foundations by Hindu fundamentalists but Singh, the ultra-secularist, did not resign from the cabinet birth. It is felt if Singh had shown courage, he would have been the PM.
Born in a feudal Jagirdar family of Rewa State in Madhya Pradesh, and a lawyer and journalist by profession, his early romance with politics was with Socialist Party of which he was associated till 1957 when he become an Independent MLA and formed a group of independent MLAs in Madhya Pradesh Assembly as its leader. In 1960 he was deeply influenced by the charismatic leadership of Pt. Jawaharlal Nehru and joined Indian National Congress. Till his last breath he remained a loyalist of Nehru-Gandhi family. He also remained committed to the ideology of the congress party based on the values of the national movement during freedom struggle.
He was sharp, brainy and could hold his own in subjects as diverse as education and economics and in tongues as contrasting as English and Hindi.
When Congress Party returned to power under the leadership of Smt. Indira Gandhi, Arjun Singh was appointed Chief Minister of Madhya Pradesh and remained CM 
uninterruptedly till March 1985. Under his leadership, Madhya Pradesh became the first State to give lease-hold rights upon plots and lands to urban slum-dwellers; pioneered a special training and employment programme to improve the lot of the urban poor; credited with the abolition of absentee ownership of cycle rickshaws and the voluntary surrender of dacoits of the Chambal valley.
After the elections in March 1985, he was sworn in as Chief Minister of Madhya Pradesh on 11 March 1985 and appointed as Governor of Punjab on the following day. He was asked to deal with the Punjab problem infested by the terrorism by then Prime Minister Rajiv Gandhi. During his Governorship he paved the way for the “Rajiv- Longowal Pact” also known as “Punjab Accord”. After he accomplished mission ‘Punjab’ in November 1985, he resigned as Governor of Punjab and joined Union cabinet as Minister of Commerce and Communication respectively under the leadership of Late Rajiv Gandhi from November 1985 to February 1988.He was elected to Eight Lok Sabha from South Delhi Parliamentary constituency in a by-election(Oct. 1986 – Feb. 1988).
He was appointed Vice-President of the Indian National Congress, on 19 January 1986, and was Member of the Congress Working Committee and Central Parliamentary Board. He was elected to the Congress Working Committee at A.I.C.C. Session, Tirupati in April 1992 with the highest margin of votes and again in July 1997.
After his difference with Congress president and then Prime Minister, PV Narsimha Rao he resigned from the Council of Ministers on 24 December 1994 and also left the Congress Party and formed his own Congress under the leadership of N D Tiwari as ‘Indira Congress’. He was elected working President of Indian National Congress (Indira) on 22 May 1995. In June 1996, he lost from Satna, lok sabha seat and again in April 1998 lost from Hoshangabad Lok Sabha seat by some maneuvering by Congressman itself. In April 2000 he was elected to Rajya Sabha and re-elected to the Rajya Sabha from Madhya Pradesh without opposition on March 2006. He rejoined the Indian National Congress in 1997 when Sonia Gandhi became Congress president. . Till his last breath he remained a loyalist of Nehru-Gandhi family. May his soul rest in peace!