Rahim was born into a highly educated family of Bengal, the son of Mawlawi Abdur Rab, who was a Zamindar in the province's Midnapore district.

[12] While he was still a judge of the High Court of Madras, Rahim gave a series of lectures at the University of Calcutta which were later published under the title The Principles of Muhammadan Jurisprudence according to the Hanafi, Maliki, Shafi'i, and Hanbali Schools.

On the contrary in India we find ourselves in all social matters aliens when we cross the street and enter that part of the town where our fellow townsmen live.

[19] In 1931, he was elected to the Central Legislative Assembly of India, and while Mohammad Ali Jinnah was overseas for the Round Table Conferences, Rahim led the Independent Party.

On 24 January 1935, he was elected as the assembly's president, which effectively ended his public involvement in partisan politics, but he retained strong views on the interests of Muslim Indians.

In June 1939, the Viceroy, Lord Linlithgow, wrote to the Secretary of State for India, Lord Zetland, after sounding out Rahim on Muslim attitudes towards the proposed Federation of India – I had not anticipated that he would be anything but right wing; but I was, I confess, a little surprised by the extreme communal vigour of his views and by the conviction with which he maintained that his co-religionists now stood, as he put it, with their backs to the wall and must fight.

[21]In October 1939, with Sir Abdullah Haroon, Rahim visited Allama Mashriqi, leader of the Khaksars, shortly after his release from jail.