While living in Kabul, Afghanistan, Mustafa Hamid married Rabiah Hutchinson, an Australian convert.
[6] A son of his, Khalid Mustafa Hamid, was killed in 1988 at 14 years old in the Paktia province of Afghanistan, as a result of a detonation of unexploded ordnance at the Jawar military training base for Afghan Arabs, which had been left there as a result of a Soviet attack on the base a few years prior.
[7] After the Soviets invaded Afghanistan, at the age of nearly 40, he went there to fight as an Islamic jihad volunteer, along with many other men from the Mideast, who became known as the "Afghan Arabs".
[8] During the 1980s, the United States provided some support to the mujahideen resistance to the Soviet Union, primarily through the CIA.
On December 31, 2010, Hamid posted a series of letters online, introducing them as "five articles, full of frankness and ardor, sent to me by one of the brothers in jihad, an old comrade in arms from Afghanistan."
The letters discuss the current jihad led by the Taliban in Afghanistan, contain constructive criticisms of the Mujahideen and Islamic Scholars and argue that the Jihadist movement needs to acknowledge and learn from its mistakes.
[10] An additional five letters, allegedly from Saif al-Adel, were posted on 23 March 2011,[11][better source needed][12] covering the Arab Spring uprisings.
There he was interviewed by Leah Farrall, an Australian counterterrorism scholar, who published an article about him in Atlantic in 2011, which also described his view of Iran's politics in Afghanistan.