The militant was identified as Mohammed Emwazi, a British citizen of Arab origin. The U.S. military said in November it was "reasonably certain" it had killed him in a drone strike.
Emwazi was described in Islamic State's Dabiq magazine by his nickname "Abu Muharib al-Muhajir".
"On Thursday, the 29th of Muharram, 1437 (Nov. 12, 2015), Abu Muharib finally achieved shahadah (martyrdom) for the cause of Allah, which he had sought for so long, as the car he was in was targeted in a strike by an unmanned drone in the city of Raqqah, destroying the car and killing him instantly," Dabiq said.
Emwazi became the public face of Islamic State and a symbol of its brutality after appearing in videos showing the murders of U.S. journalists Steven Sotloff and James Foley, U.S. aid worker Abdul-Rahman Kassig, British aid workers David Haines and Alan Henning, Japanese journalist Kenji Goto and other hostages.
Shown in the videos dressed in black, a balaclava covering all but his eyes and the bridge of his nose, Emwazi became one of the world's most wanted men.
Born in Kuwait in 1988, Emwazi was taken to Britain by his family when he was 6 years old and graduated in computer programming in London.
The U.S.-British missile strike believed to have killed him was months in the preparation but came together at lightning speed last November as two U.S. MQ-9 Reaper drones and one British MQ-9 cruised above the Syrian town of Raqqa, according to U.S. officials.