A man of deep religious convictions, he also had a deep interest in Islamic mysticism, a fact which probably reflects the influence of his parents and also his associate Maulana Muhammad Ali Jauhar. From 1919 to 1920, both of them actively participated in the Khilafat Movement. Later, Sardar Abdur Rab Nishtar remained member of Indian National Congress from 1927 to 1931, was elected Municipal Commissioner, Peshawar Municipal committee, successively from 1929 to 1938, joined All-India Muslim League, became a confidante of Pakistan's founder Muhammad Ali Jinnah. From 1932 to 1936, Nishtar was a member of All India Muslim League Council, member NWFP legislative Assembly 1937 to 1945, Finance Minister NWFP 1943–45, member AIML Working Committee, 1944–1947, represented the All India Muslim League at the Simla Conference in 1945. Abdur Rab Nishtar was ousted from provincial politics through the political maneuvers of a rival political leader Abdul Qayyum Khan in 1946. Abdul Qayyum Khan was an outcaste from the Indian National Congress Party, who then vigorously opposed that political party after his ouster from it, especially he was against the union of the Indian subcontinent in a single country and was working for the creation of an independent Muslim state.
Nishtar was considered a serious contender for the post of Prime Minister after Liaqat Ali Khan's assassination. His appointment was blocked by senior secularists and liberal officials including the future President Iskander Mirza because of Nishtar's conservative and Islamic views.
Became Opposition Leader against corrupt politicians
He subsequently fell out with the government over the dismissal of Prime minister Khawaja Nazimuddin's government by Governor GeneralGhulam Muhammad. Refusing to be involved in what he perceived as an undemocratic act, Nishtar went into opposition. In 1956, when the first Pakistani constitution was adopted, Sardar Abdur Rab Nishtar was elected president of the party against the wishes of President Iskandar Mirza and then prime minister Chaudhry Mohammad Ali who were backing Dr. Khan Sahib as West Pakistan chief minister while Nishtar wanted an Muslim League man for the office. But a big majority of the League leaders, including Nawab Mushtaq Ahmad Gurmani and Mumtaz Daultana, supported Iskander Mirza.
Leader of Muslim League
He subsequently took over the leadership of the Muslim League party and the League was expected to do well in West Pakistan in the planned 1959 elections but unfortunately he died before that. He served as President, Pakistan Muslim League from 1956 to 1958.
Abdur Rab Nishtar died of a heart attack on 14 February 1958 in Karachi. He had been suffering from heart disease and high blood pressure since 1953. Nishtar Medical College and Nishtar Hospital in the city ofMultan are named in his honor. Nishtar Park and Nishtar Road in Karachi are named after him. He was buried at Mazar-e-Quaid near the Tomb of Muhammad Ali Jinnah, the founding father of Pakistan to acknowledge his services in the cause of Pakistan. Abdul Rab Nishtar had a reputation of being a sincere political leader and a man of amicable nature. With his political activities, he contributed greatly to All-India Muslim League and the Muslims living in the Indian subcontinent, creating political consciousness and Islamic spirit among them. Abdul Rab Nishtar was a close friend of both Maulana Muhammad Ali Jauhar and Maulana Shaukat Ali. At one point during their association, Muhammad Ali Jauhar had told Nishtar that he opposed Jinnah for re-organization of the All-India Muslim League. After finding out all the details of Jinnah-Jauhar discussion, Nishtar decided to support Jinnah's proposal and even succeeded in convincing Jauhar to do the same.