From 1932 to 1936 Fakih was a member of the Muhammadiyah's regional council, serving concurrently as the editor of the organisation's official magazine Bintang Islam and on the Legal Affairs Committee.
On 21 September 1937, Muhammadiyah, the conservative Nahdatul Ulama (NU), the merchants' cooperative Sarekat Islam, and several other Islamic groups - which for the past decade had been feuding - united to form an umbrella group: the Indonesian Islamic Assembly (, or MIAI), based in Surabaya.