Barrett boarded a Pakistan International Airlines flight to New York from Lahore airport on Saturday, a spokesperson for the national carrier said.
He was arrested on August 6 this year by law enforcement personnel at a guest house in Islamabad.
Barrett came to Pakistan despite being deported to the US and blacklisted from the country in 2011, Dawn online reported.
After being imprisoned on August 13 under the Foreigners Act, Barrett was released from Adiala prison in Islamabad on Friday night and transported to Lahore for deportation, sources said.
He said that he came back to Pakistan to explore the possibility of permanently moving here.
He was arrested in 2011 while taking photographs of sensitive installations in Islamabad, but was asked to leave the country after being cleared of all charges against him by the Supreme Court of Pakistan.
During his earlier stay in the country he married a Pakistani woman. The couple has two children.
