Hassan Hassan Saeed Al-Jabouri, also known as Abu Taluut, was killed 18 miles south of Mosul in the village of Qayyara, according to Maj. Gen.Watheq Al-Hamdani, a senior regional Iraqi police commander who is leading the government's efforts to retake Mosul from ISIS.
Jabouri is the second ISIS-appointed governor of Mosul killed by airstrikes and had been in office for less than 25 days.
Earlier this month, U.S. airstrikes killed one of his predecessors, Radwan Taleb Al-Hamdouni, according to U.S. security officials.
Mosul is a key stronghold for ISIS fighters and was taken from Iraqi forces earlier this year. The Pentagon said that it has a strategy to retake the city beginning in January.
Meanwhile, more than 100 people were injured or killed in six airstrikes by Syrian forces on the ISIS held city of al-Bab and the town of Qbasin in the northeast of Aleppo, according to the Syrian Observatory for Human Rights.
In the village of Abo Qassayed, 30 ISIS militants were killed Tuesday as Syrian Kurdish forces captured that town held by ISIS, according to the observatory.
ISIS captured a Jordanian fighter pilot Wednesday after his plane crashed over Raqqa.
"Evidence clearly indicates" that the terrorist group "did not down the aircraft," U.S. Central Command said in a statement.