Hart was the most important and most influential Westerner in Qing dynasty China. According to Jung Chang, he transformed Chinese Customs "from an antiquated set-up, anarchical and prone to corruption, into a well-regulated modern organisation, which contributed enormously to China's economy." Professor Rana Mitter of the University of Oxford writes that Hart "was honest and helped to generate a great deal of income for China." Sun Yat-sen described him as "the most trusted as he was the most efficient and influential of 'Chinese.'"