He later completed neurosurgery training at George Washington University, and started his own medical practice in the Washington, District of Columbia area.
Prior to the invasion of Iraq Karim had served in numerous Kurdish and Iraqi opposition groups. Karim became involved in politics at university, being elected to the leadership of the Kurdish Student Union in 1971, and then later joining the peshmerga in 1972. Karim left Iraq in 1975.
Karim became an American citizen and lived in Maryland until 2009, when he returned to Kirkuk.
Karim was in the emergency room when American President Ronald Reagan was shot in March 1981. He was subsequently elected as governor of Kirkuk Governorate by Kirkuk"s Governorate Council on 29 March 2011, and was sworn in on 3 April 2011.
Following President Jalal Talabani"s stroke on December 17, 2012, Karim served as the head of Talabani"s medical team when Talabani is in Iraq, although the majority of his medical treatment has been carried out in Germany.
Karim returned to Iraq in 2009 to stand for the Kurdistan Alliance in the parliamentary election, and was elected as a member of parliament for Kirkuk.