The former head of Iraq's Iran-linked Popular Mobilisation militias returned to his dual posts as chairman of the militias and national security adviser to Prime Minister Adel Abdul Mahdi, ahead of a Parliament session to consider new cabinet appointments on Tuesday.
Falih Al Fayadh retook his seat at a meeting of Iraq's National Security Council on Sunday after he was sacked from his positions by caretaker prime minister Haidar Al Abadi in August for political behavior.
Mr Al Fayadh has also been nominated to head the country's powerful Interior Ministry, which has been under the control of ministers close to Iran since 2010. His nomination has been opposed by the political bloc of populist Shiite cleric Moqtada Al Sadr, which says it wants to limit outside influence in Iraqi politics.
Iraq's government has been deadlocked as politicians spar over appointments for several key ministries, including the Interior and Defense.
Mr Abdul Mahdi was confirmed as premier in October without a full cabinet after parliament approved just 14 of 22 ministerial posts.
The parliament is slated to again consider the rest of the cabinet nominees on Tuesday, though expectations for a breakthrough are low.
The Popular Mobilisation Forces were formed in 2014 to stop the advance of ISIS militants through Iraq. They include several militias funded and trained by Iran.