His 30-year regime now facing intense pressure, Mubarak announced Saturday that the Arab world's most populous nation would once again have a deputy leader. For that role, he tapped Omar Suleiman, the intelligence chief who has been a powerful behind-the-scenes player for a long time.
Suleiman's appointment as vice president was seen widely as an attempt by Mubarak to restore order. He is well respected by the military and is credited with crushing an Islamic insurgency in the 1990s, for which he earned the ear of Western intelligence officials thirsting for vital information about regional terrorist groups.
He has also long been mentioned as a possible successor to Mubarak, along with the aging ruler's son, Gamal, and some analysts viewed his deputy appointment as a way for Mubarak to make a graceful exit.
"His loyalty to Mubarak seems rock solid," a former U.S. ambassador wrote in a classified U.S. diplomatic cable leaked to the website WikiLeaks.
"Suleiman himself adamantly denies any personal ambitions, but his interest and dedication to national service is obvious," said the 2007 document.
If Suleiman's name is not well known, it is intentional. As head of the Egyptian General Intelligence Organisation, known as the Mukhabarat, he has lurked in the shadows of Mubarak's regime, earning him a nickname of "the secret minister."
He has even made trips to Washington without public notice. On one such visit in 2006, he presented former Secretary of State Condoleezza Rice with a personalized silver box worth $420.
"He is someone that we know well and have worked closely with," said State Department spokesman P.J. Crowley.
But if Suleiman's presence has been opaque, his role certainly has not.
Suleiman is even credited with saving Mubarak's life. On a state visit to Ethiopia in 1995, Mubarak was to have traveled in a normal vehicle but Suleiman insisted that the president's armored Mercedes be flown in from Cairo.
Accounts of an assassination attempt on Mubarak vary but it's believed that Suleiman was sitting next to Mubarak when a hail of bullets pinged off the car. The bond forged that day cemented their relationship.
Born in an impoverished area of southern Egypt in 1935, Suleiman chose the military as a career, according to a Foreign Policy magazine biography.
He rose through the ranks of the Egyptian infantry to a lieutenant general. After his country allied itself with the United States, he attended the John F. Kennedy Special Warfare School and Center at Fort Bragg, North Carolina, in the 1980s, Foreign Policy reported.
He was tapped for Egypt's top intelligence post in 1993, at a time when the Arab world's most populous nation was wracked with terrorist attacks targeting tourists and essential infrastructure.
Defense and security analysis company IHS Jane's says Suleiman's interaction with the Israeli Mossad as well as the Central Intelligence Agency catapulted him to a central role in Egypt's security apparatus.
In 2001, he led Egyptian efforts to confront a Palestinian uprising next door. Later, he played a crucial role in the formation of a new Palestinian government headed by Mahmoud Abbas, according to Jane's.
Now, Omar Suleiman's name is etched into the annals of Egyptian history as the man entrusted to defend an embattled leader. He saved Mubarak's life before, but will he be able to preserve his power?
