China’s drug control arena is undergoing an ambivalent governance shift from the (quasi) criminalization of drug use to the medicalization of addiction as a chronic brain disease. However, the recasting of drug use as a medical condition worthy of “human-centered” care is challenging given the deeply rooted zero-tolerance sentiment toward drug-related issues in China. Based on sixteen months of ethnographic fieldwork conducted at state-run methadone maintenance treatment facilities in Yunnan province from 2013 to 2019, this study investigates how drug users responded to the uneasy medicalization process during their everyday encounters with the Chinese state and state agents. Although the treatment program provided participants with a medically and politically legitimate status as patients, drug users employed dramatically different frameworks to re-interpret this state-assigned identity in order to claim a kind of moral legitimacy. This paper also argues that such a claim was achieved through drug users’ efforts in inventing a “moralist” relationship with the Chinese state and the broader society.