Adnan Garar was a senior member of the Somali terror group and believed to have been behind the September 2013 attack on a Nairobi mall that killed 67 people.
Garar's death in the drone strike was confirmed in a Pentagon statement.
"On March 12 at approximately 7:30 a.m. Eastern Time, working from actionable intelligence, U.S. forces using unmanned aircraft struck a vehicle carrying Adan Garar, a member of al-Shabaab's intelligence and security wing, in the vicinity of Diinsoor, Somalia," according to the statement. "The attack was a success and resulted in the death of Garar."
The statement described Garar as a "key operative for coordinating al-Shabaab's external operations, which target U.S. persons and other Western interests in order to further al Qaeda's goals and objectives." It said he " posed a major threat to the region and the international community and was connected to the West Gate Mall attack in Nairobi, Kenya."
His death was described as "another significant blow to the al Shabaab terrorist organization in Somalia."
Last Friday, the Pentagon confirmed a "counterterrorism" military mission in Somalia drone strike against an al Shabab leader, but declined to identify the target because the mission's success was still being assessed.
Over the last year, the U.S. military has conducted several drones strikes that have killed senior al Shabab leaders including one last September that killed Ahmed Gobane the group's co-founder.