Nagin, his wife, and one of his guards had been quarantined since Sunday, after a passenger on their flight from New Jersey showed flu-like symptoms.
Quiett said Nagin plans to fulfill the second leg of his overseas trip with speeches in Australia.
Nagin released a statement thanking Chinese officials.
"On behalf of my family and the citizens of New Orleans, I would like to express my deepest appreciation to the medical officials in Shanghai, Shanghai Officials, the US Embassy and others for prioritizing the health and safety of myself, my wife, Mrs. Nagin and the city's law enforcement officer. Thank you. Thank you.
We are departing Shanghai today is the best of health and spirits."