When the Department of Political Economy was bisected, he chose the department of Political Science.
In 1936, he passed Master of Arts in the first class and joined as a lecturer in the same department. After the Second World War, Abdur Razzak went to London, United Kingdom to study under Harold Laski at London School of Economics. He returned home without any formal degree after Harold Laski had died in 1950 and carried on teaching in the department of Political Science at the University of Dhaka until 1975.
He also taught in the departments of Economics and International Relations.
As a teacher, he gained legendary status. His admirers "called him reverently a teacher of teachers".
During the Bangladesh Liberation War, he witnessed the March 1971 Dhaka University massacre. The Pakistanis came to arrest him at his home, but alerted by their kicking at his door, he escaped out the back.
The Yahya Khan-government sentenced him in absentia to a fourteen-year rigorous imprisonment, accusing him of "treasonable" acts.
Though Abdur Razzaq, apart from some essays and lectures, has no published works, many intellectuals have admitted his influence on their published works. Ahmed Sofa wrote his book: যদ্যপি আমার গুরু on Abdur Razzaq. Salimullah Khan wrote a book on his famous lecture ‘’Bangladesh: State of the Nation’’.
Muntassir Mamoon, Humayun Azad and many others reminisced about him and praised him highly in their many books
To acknowledge his unique status as a teacher, the Government of Bangladesh honored him with the distinction of National Professor in 1975. In 1973, the University of Delhi honored him with a Ph Doctorate.
Abdur Razzaq"s political ideas influenced anti-Ayub-government movements during the 1960s. To get rid of his influence, the Ayub regime tried to "dismiss him from his teaching position at Dhaka University on the allegation that he was not mindful of his duties as a teacher, but which the government failed to establish in the court". Sardar Fazlul Karim published a book: ঢাকা বিশ্ববিদ্যালয় ও পূর্ববঙ্গীয় সমাজঃ অধ্যাপক আব্দুর রাজ্জাক-এর আলাপচারিতা based on his interviews of Abdur Razzaq.
He claimed to have had as his students more than 70 members of Parliament, among whom Sheikh Mujibur Rahman is the most notable.