A statement by US Central Command (CENTCOM) said: "CENTCOM Forces conducted a kinetic strike in Idlib province, Syria, June 27, targeting Abu Hamzah al Yemeni, a senior leader of Hurras al-Din, an Al Qaeda-aligned terrorist organization."
"The removal of this senior leader will disrupt Al-Qaeda's ability to carry out attacks against US citizens, our partners and innocent civilians around the world," the statement added.
Al-Yemeni was said to be travelling alone on a motorcycle in the northwestern province at the time of the strike.
A US official told CNN that the Pentagon was "highly confident" that the strike, carried out by a drone, killed the senior leader.
The strike follows the US-led coalition's arrest of a senior Daesh leader in Aleppo, northern Syria, identified as Hani Ahmed Al-Kurdi. The experienced bomb maker, who rose to the top ranks of the terrorist organisation in Syria, was described by the US as having been "responsible for coordinating terrorist activities across the region".