He served as a senior Justice of the Supreme Court of Pakistan (Shariat Appellate Bench). He was also director of the Islamic Academy of Manchester UK. He founded a purpose-built mosque, Gity Jamia Masjid, in Manchester. Mahmood was the Shaykh-ul-Hadith of
Jamia Ashrafia, Lahore, and the head of the Islamic Center Manchester. In the UK during the 1960s, he worked with Asif Husain Farooqi and
Yusuf Motala and worked alongside him (before establishing Dar-ul-Uloom Bury). He travelled to over 50 countries in his lifetime with regard to his Islamic works, focusing on establishing the message relating to the
Finality of the Prophethood.
Manzoor Ahmad Chinioti accompanied Mahmood on many of the travels relating to these works; most notably spending a 6-month period in South Africa in the 1970s whilst contention relating to
Khatm-e-Nabuwwat was rife - soon after the opposing view began to be spread in these areas. Throughout his lifetime, Mahmood established many
Masājid and Islamic centres across the world, especially in poverty-stricken areas - for example within
Ghana,
Gambia, and many throughout
South-East Asia, whilst also setting-up many other charities in these areas to provide aid in the form of orphanages, health centres, and food banks. ==Literary works==