Founded as a splinter faction of the Sadrist Movement, Jaysh al-Mu'ammal is supported by Iran and former Iraqi Prime Minister Nouri al-Maliki.

One of the leading commanders of the Sadrist Peace Companies, Sa'ad Sawar, openly broke with Muqtada al-Sadr and travelled to Damascus,[5][2] where he joined another Iraqi militia, Liwa Assad Allah al-Ghalib fi al-Iraq wa al-Sham, to fight against the Syrian insurgents.

[3] After returning to Iraq, Sa'ad Sawar consequently managed to rally a substantial number of dissatisfied Sadrists to his cause,[5] and announced the foundation of "Jaysh al-Mu'ammal" in June 2016.

[5] Unlike Muqtada al-Sadr, who is focused on Iraq, Sa'ad Sawar has emphasized his readiness to provide military support to Shia groups outside of his home country.

His group consequently operates in both Iraq as well as Syria, and has also declared its willingness to support the Houthis in the Yemeni Civil War, and to fight with the Bahraini opposition against the Sunni House of Khalifa.