Ishaq's grandfather Rabi'a ibn Asim was a Basran who had fought and died in the Battle of the Camel in 656, after which the family moved to the Jazira.

Ishaq's father Muslim fought alongside the Qaysi chief Zufar ibn al-Harith al-Kilabi during his rebellion against the Umayyads from the fortified Jaziran town of Qarqisiya in 684–691.

[3] In 743/744, he was appointed as commander of Derbent (Bab al-Abwab) and governor of the combined province of Armenia and Adharbayjan, and he accompanied Marwan in 745/746 in the fighting in the Jazira, during the Third Fitna.

[1] At that time, following the defeat of Marwan at the hands of the armies of the Abbasid Revolution, he assembled the remnants of the Umayyad armies and rallied Marwan's supporters in Armenia and the Jazira (the areas which had been Marwan's personal power base) and established himself with reportedly 60,000 men at the fortress of Sumaysat, awaiting the Abbasid advance.

In the event, a negotiated settlement was reached between Ishaq and Abu Ja'far (the future Caliph al-Mansur), and many of the pro-Umayyad leaders became accepted in the ranks of the Abbasids.