The Pentagon said Tahliil Abdishakur's "death will significantly impact al Shabaab's ability to conduct attacks."
A Somali Islamist group leader, who has a $3 million bounty, has surrendered, according to a Somali government source and local media.
A spokesman of the militant group said it "targeted the enemies at a time they were celebrating Christmas."
Nearly 350,000 fled war and conflict by sea in 2014, the UN Human Rights Agency said Wednesday.
At least 36 non-Muslim workers were killed, including two being beheaded
Though operations continue in Pakistan and Yemen, Somalia has third consecutive drone-free month.
Gunmen ordered non-Muslims off a bus Saturday and shot 28 dead. Muslim passengers were spared.