Although the Treasury Department announcement identified the group as Al-Nusra Front, the jihadist force changed its name last year to Fateh al-Sham Front, after supposedly breaking its ties with Al-Qaeda.
The Treasury said Iyad Nazmi Salih Khalil was, as of a year ago, Al-Nusra Front's (ANF) third-highest ranking person and its emir for coastal Syria.
Before that, he "empowered ANF's security and intelligence operatives responsible for assassinations, ran prisons notorious for torture, and encouraged the looting of vehicles and possessions of Free Syrian Army members," the Treasury said in a statement.
"From overseeing militant operations to developing Al-Nusrah Front's strategy, these senior Al-Nusrah Front leaders and al-Qaeda terrorists are responsible for providing key support to the violent terrorist group," said John Smith, acting director of the Treasury's Office of Foreign Assets Control.
The sanctions, which follow similar UN actions against the pair, aim to freeze their assets, lock them out of the global financial system, and prevent them from travelling internationally.