He was one of the four hijackers of United Airlines Flight 93, which was crashed into a field in Stonycreek Township, Pennsylvania, following a passenger revolt, as part of the 11 September attacks.

He left his family in 2000 to complete the Hajj, but later went to Afghanistan bound for an al-Qaeda training camp where he befriended other future hijackers and would soon be chosen to participate in the attacks.

That autumn he left his family home in Abha in the summer of 2000 to complete the Hajj, but never returned – instead travelling to the Al Farouq training camp in Afghanistan where he met and befriended Waleed and Wail al-Shehri, two brothers from Khamis Mushayt in the same province, and Saeed al-Ghamdi.

[2] Dubbed "Abu Hashim", al-Nami was considered "gentle in manner" by his colleagues, and reported that he had a dream in which he rode a mare along with Muhammad, and that the prophet told him to dismount and fight his enemies to liberate his land.

[1] During his time at al-Farooq, there is a curious mention under Mushabib al-Hamlan's details that al-Nami had recently had laser eye surgery, an uncited fact that does not reappear.

al-Nami's visa application has since been reviewed, and while he mentioned that al-Hamlan will be travelling with him, he listed his occupation as student but failed to provide an address for his school, and listed his intended address in the United States merely as Los Angeles – in the end he never used this visa to enter the United States, and reported his passport (C115007, which showed evidence of travel to Afghanistan) as "lost", and procured a new one from Jeddah (C505363).

In March 2001, Ahmed al-Nami appeared in an al-Qaeda farewell video showing 13 of the "muscle hijackers" before they left their training centre in Kandahar; while he does not speak, he is seen studying maps and flight manuals.

On 28 August, al-Nami and Ahmed al-Haznawi reportedly bothered a Delray Beach resident, Maria Siscar Simpson, to let them through her apartment to retrieve a towel that had fallen off their balcony onto hers.