He has used Abu Muhammad, Abu Fatima, Muhammad Ibrahim, Abu Abdallah, Abu al-Mu'iz, The Doctor, The Teacher, Nur, Ustaz, Abu Mohammed, Abu Mohammed Nur al-Deen, Abdel Muaz (Abdel Moez, Abdel Muez), and other names as aliases.
Al-Zawahiri was born to a middle class family in Maadi, Egypt, a suburb of Cairo, and was reportedly a studious youth. However, events pushed him in a more radical direction (possibly the Six Day War in 1967). By fourteen he had joined the Muslim Brotherhood, a radical Islamist group. By 1979 he had moved on to Islamic Jihad, where he eventually became one of its leading organizers and recruiters. He was one of hundreds arrested following the assassination of Anwar Sadat, but the Egyptian government was unable to prove any connection between al-Zawahiri and the crime and he was released.
In the 1980s he journeyed to Afghanistan to participate in the mujahideen resistance against the Soviet Union's occupation. There he met Osama bin Laden, who was running a base for mujahideen called Makhtab al-Khidamat (MAK); both of them worked under the tutelage of the Palestinian Abdullah Azzam.
In 1990 al-Zawahiri returned to Egypt, where he continued to push Islamic Jihad in more radical directions employing knowledge and tactics learned in Afghanistan. In 1997 he was held responsible for the massacre of 58 (or 67) foreign tourists in the Egyptian town of Luxor, which earned him the death penalty in that country.
Following the U.S. invasion of Afghanistan, al-Zawahiri's whereabouts are unknown; press reports in 2002 said he had been killed by unknown forces, but in early September of 2003 a video of al-Zawahiri and bin Laden, as well as an audiotape, was released to the al-Jazeera network in Qatar, purporting to prove that both are still alive.