After graduating from Taipei Municipal Jianguo High School, Hao studied chemistry at Fu Jen Catholic University (BS degree), obtained a Master's Degree from Massachusetts Institute of Technology (MIT), and a PhD in Atmospheric Chemistry from Harvard University.
In 1991, he works in the US Department of Agriculture and Forest Services in the city of Missoula.
In 1994, he became an author of the Intergovernmental Panel on Climate Change (IPCC). In the same year, the first Climate Change Report was published by the IPCC. He was responsible for Rocky Mountain Climate Monitoring.
Until 2014, he has been the author or co-author of more than 70 publications in specialized magazines. His publications are widely cited by major institutions and universities around the world.