Al-Tilmisani nacque a Darb al-
Ahmar (distretto del Cairo) nel 1904. Avvocato, al-Tilmisani si unì ai Fratelli Musulmani già nel 1933 e fu inserito nei gangli decisionali dell'organizzazione dal suo fondatore e Guida Generale, [[Hasan al-Banna]].
was from a family of prominent landowners, which owned 300 feddans ( acres) and seven houses. His deputy, and a later successor as General Guide, [[Mustafa Mashhur]], was also from a family of wealthy landowners. Their prominence and social status led historian Robert Springborg to conclude at the end of the 1980s that, " It can reasonably be claimed that those currently in control of the Muslim Brothers are of the Islamic [[ infitah]] bourgeoisie who ' bought' the organization with resources acquired through collaboration with the Sadat regime"<ref>Springborg 1989, 236</ref>
Despite heading the group during this period of cooperation with the state, al-Tilmisani was imprisoned three times, once in 1954, as an activist during the difficult Nasser years, and twice while at the head of the group, during Sadat's mass roundup of opponents in 1981, and again under Hosni Mubarak in 1984.