After the capture of Saddam Hussein in Iraq, he joined his defence team, while still President of the Jordanian Bar Association.
[3] He resigned in 2008 when the Jordanian cabinet passed a draft law barring professional organisations from engaging in politics.
[3] In April 1998 Mjalli voiced his displeasure about the ban on press coverage regarding the case of Leith Shubeilat, a former member of parliament and opposition figure, who was charged inciting an illegal demonstration.
Mjalli made his comments in his capacities as the lawyer of Shubeilat and the President of the Jordanian Bar Association.
They argued that "given the invasion of Iraq [had] no legal basis, US-led occupation forces [had] no right to change or cancel the Iraqi constitution".
Mjalli joined the protesters, declaring he was participating in his capacity as Daqamseh's defence lawyer, which he had earlier been at the trial.
[12] Mjalli resigned on 26 May 2011 when Khaled Shahin, a businessman who had been convicted of bribery, was released to receive medical treatment abroad.
[13][14] Mjalli died of a heart attack on 12 October 2014, aged 77, and was buried in his hometown of Kitta in Jerash Governorate.