Marwan ibn Muhammad was a member of the Marwanid household of the Umayyad Caliphate.
In A.H. 114 (732–733) Caliph Hisham appointed Marwan governor of Armenia and Azerbaijan. In A.H. 117 (735–736) Marwan invaded Georgia, devastated it and then took three fortresses of the Alans and made peace with Tumanshah. In A.H. 121 he launched further raids and obtained tribute. In A.H. 126 on hearing news of the plotting to overthrow al-Walid II Marwan wrote to his relatives from Armenia strongly discouraging such an act. He urged them to harmoniously preserve the stability and well being of the Umayyad house.
When Yazid III persisted in overthrowing al-Walid II, Marwan at first opposed him, then rendered allegiance to him. On Yazid's early death, Marwan renewed his ambitions, ignored Yazid's named successor Ibrahim and became caliph. Ibrahim initially hid, then requested Marwan give him assurances of personal safety. This Marwan granted and Ibrahim even accompanied the new caliph to Hisham's residence of Rusafah.
Marwan named his two sons Ubaydallah and Abdallah heirs. He appointed governors and proceeded to assert his authority by force. However, anti-Umayyad feeling was very prevalent, especially in Iran and Iraq. The Abbasids had gained much support. As such, Marwan's reign as caliph was almost entirely devoted to trying to keep the Umayyad empire together.
Marwan took Emesa (Homs) after a bitter ten-month siege. Al-Dahhak ibn Qays al-Shaybani led a Kharijite rebellion. He defeated the Syrian forces and took Kufa. Sulayman ibn Hisham turned against Marwan, but suffered a severe defeat. The Kharijites advanced on Mosul and were defeated. Sulayman joined them. Al-Dahhak's successor al-Khaybari was initially successful in pushing back Marwan's centre and even took the caliph's camp and sat on his carpet. However, he and those with him fell in fighting in the camp. Shayban succeeded him. Marwan pursued him and Sulayman to Mosul and besieged them there for six months. Then reinforced the caliph drove them out. Shayban fled to Bahrayn where he was killed; Sulayman sailed to India.