The vice-principal of Jinnah Medical and Dental College was shot by unidentified gunmen, a media report said on Friday.
Police identified the victim as American national Debra Lobo, 55. She was attacked on Thursday by four gunmen after she left the college, Dawn online reported.
She was rushed to a hospital, where doctors said she was "out of danger" after hours of treatment.
A police official said that a leaflet found near the crime scene said "we will burn America" and that the attack was to avenge the recent killing of five militants in an "encounter" in Karachi's Keamari area.
He said the leaflet did not carry a logo of any militant organisation but claimed that they were "lions of Islamic State (IS)" and "falcons of the caliph".