He has a distinct London accent and is believed to be a British citizen of Nigerian descent who, along with the second suspect shot by police after Wednesday's attack in Woolwich, south-east London, is believed to have converted to a radical form of Islam around 10 years ago.
His identity has not been formally released, but emerged on Internet forums and Twitter hours after the soldier was butchered on the busy London street near Woolwich Army barracks and his name is now being quoted by BBC and Sky News sources here.
Both suspects are being treated in separate hospitals while under arrest and their condition is said to be serious.
Adebolajo was reportedly known to Al Muhajiroun, a radical and banned Islamist organisation in the UK, and went by the name of Mujahid.
Anjem Choudary, the former leader of the group, claims he had converted to Islam in 2003 but had stopped attending meetings of Al Muhajiroun and its spin-off groups two years ago.
Video footage filmed by an onlooker and broadcast by Britain's ITV news channel showed Adebolajo with hands covered in blood and holding a bloodied meat cleaver and a knife.
"I apologise that women had to witness this today but in our lands, our women have to see the same," he said. "You people will never be safe. Remove your government, they don't care about you."
The soldier who was killed has not been named on his family's request. He was reportedly first hit by a car before the two men in that vehicle came out with a machete and a gun and started to attack him.
Witnesses said the attackers had approached police when they arrived and were then shot. The two men were said to have shouted "Allahu Akbar" as they carried out the attack.