Zainuri was born around 1966/67[2][1] in Bota, Perak,[3] and studied at Madrasah Misbahul Falah, Baling District, Kedah before continuing his studies at the Abu Bakar Islamic University in Karachi, Pakistan. There, he joined the Islamist group Kumpulan Mujahidin Afghanistan and went to Afghanistan, fighting against the Democratic Republic of Afghanistan for two years. Zainuri participated in battles in Kunar Province, Khost Province and the Battle of Jalalabad, gaining "vast battlefield experience".[4]