Zawahiri has been Al Qaeda's operational leader for years – he helped plan 9/11 – but he lacks bin Laden's charisma and many Al Qaeda experts say it is unlikely he'll command the loyalty that bin Laden did, The Christian Science Monitor reported last month.
But Mr. Zawahiri, a surgeon and the scion of an upper-class Egyptian family, strikes many as haughty and droning with little of the ability Mr. bin Laden had to inspire. Irascible, he is given to fueling obscure ideological conflicts within jihadi ranks; Al Qaeda itself reportedly split into two factions before bin Laden’s death, with Zawahiri in charge of the spinoff, according to Pakistani intelligence officials.
Three decades ago, a member of Zawahiri’s Islamic Jihad group recognized his lack of leadership, reportedly telling him, “No matter what group you belong to, you cannot be its leader.”
Zawahiri joined Al Qaeda in 1998 and crafted the organization's strategy through several high-profile attacks and campaigns: the USS Cole bombing in 2000 in Yemen, the 9/11 attacks, and the stoking of civil war in Iraq following the US invasion.