Senior ISIS leader Tariq Al-Harzi was killed by a coalition airstrike in Shaddadi, Syria on June 16, reported CNN.
Known as the "emir of suicide bombers," Hazri was added to the US Designated Terrorist List in 2014.
It is believed that he was involved in group's operations beyond Iraq and Syria too.
ISIS has established a foothold in Libya and gained affiliates in Nigeria and Egypt, among other places.
Reports also said that al-Harzi, a Tunisian, was freed from Abu Ghraib prison during an ISIS raid in July 2013. The US
State Department had offered a $3 million reward for information on al-Harzi.
Al-Harzi was one of the first prominent terrorists known to have joined up with ISIS in 2013.
ISIS militants conquered large swathes of Iraq and Syria last year, in a brutal campaign to establish an Islamic caliphate.
Airstrikes against ISIS began in Iraq on August 8 and Syria on September 23. It was launched by a multinational coalition, including Arab countries under US leadership.