Ali bin Muhammad Ali al-Sulayhi was the founder and sultan of the Sulayhid dynasty in Yemen. He established his kingdom in 1047 and by 1063, the Sulayhids controlled had unified the entire country of Yemen as well as the Muslim holy city of Mecca under his leadership. Al-Sulayhi was killed in 1066 during a tribal vendetta between the Sulayhids and the Najahids of Zabid. He was succeeded by his son, Ahmad al-Mukarram.

Al-Sulayhi was born and raised in the village of Jabal near Manakhah. He was the son of Muhammad bin Ali al-Sulayhi, the chief qadi ("judge") of Jabal Haraz. His father was a leading Sunni Muslim and educated al-Sulayhi on the Shafi'i madhab ("school of law.") Nonetheless, al-Sulayhi converted to Ismailism, a branch of Shia Islam, after coming under the influence of the da'i ("missionary") Amir al-Zawahi. Zawahi had kept his Ismaili faith private and was well-regarded by al-Sulayhi's father who employed him to teach his son. However, al-Zawahi, who also served as the Chief Da'i of the Ismailis, secretly taught al-Sulayhi the system of canon law used by the Fatimid Caliphate and the allegorical interpretation of the Qur'an employed by the Ismailis known as tawil.

Al-Sulayhi succeeded al-Zawahi as Chief Da'i of Yemen after the latter's death. He married his cousin Asma bint Shihab in the 1030s. She who would later assist him during his reign over the region. Al-Sulayhi kept his religion and his post as Chief Da'i of the Ismailis relatively secret. Starting in 1032, he served as amir al-hajj, leading and protecting the annual hajj ("pilgrimage") caravan to Mecca through Yemen and Asir's rough terrain. He continued in this capacity for 15 years, lecturing groups of pilgrims, including regional Muslim leaders of various ranks, on Ismaili thought on behalf of the Fatimid caliphs. The position, which was a prestigious one among Muslims, also provided al-Sulayhi with a steady and high income.

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