Politically, he played an important role in Sudanese independence, negotiating the 1952 "Gentlemen's Agreement" with Egypt, which paved the way for self-government and fair elections while advancing Sudanisation of public institutions.

After independence, Abdallah became a senior assistant to Imam Abd al-Rahman al-Mahdi and joined the executive committee of the National Umma Party.

His good relationship with Egypt played an important role in Sudan's attainment of its full rights, especially since there was trust between him and Major General Muhammad Naguib.

[2][5][6] On 19 October 1952, an agreement was reached between the Egyptian Government and Abdallah al-Fadil al-Mahdi of the Sudanese Independence Front.

This agreement gave the green light for Sudan to achieve self-government by the end of 1952, followed by the exercise of the right to self-determination within the subsequent three years.

In addition, the agreement envisioned the establishment of an international commission tasked with overseeing the electoral processes within Sudan, ensuring fairness and impartiality.

Lastly, it laid the groundwork for a "Sudanization Committee" with the specific aim of expediting the replacement of foreign personnel with Sudanese individuals across various sectors, including administration, the police force, and other public appointments.

[8] Abdallah was one of the Imam Abd al-Rahman al-Mahdi senior assistant,[2] and member of the National Umma Party (NUP) executive committee.

[2] Abdallah and the National Umma Party played a role in resisting Ibrahim Abboud's rule, which sparked the Mawlid massacre on 21 August 1961, where 17 from the Ansar were killed by the army.

[11] During Abdallah tenure, he joined the first line-up which came to power from 10 June 1965, and it was composed of Ismail al-Azhari (Democratic Unionist Party), and Khader Hamad (DUP), Abdullah al-Fadil al-Mahdi (NUP),[12] Abdel Halim Mohamed (NUP), and Luigi Adwok Bong Gicomeho (Southern Front) who resigned on 14 June 1965 and was replaced by Philemon Majok.

[2] Abdallah married Umm Al-Kiram Sharif in 1914, and together they had 8 children including Kamal,[2] who was the Justice and Public Works minister in 1968.