Individuals who have experienced chronic homelessness often have unmet physical and mental health needs and experiences of trauma and stigma. This study aimed to measure, for the first time, health activation (self-advocacy and empowerment) levels among formerly homeless adults living in Permanent Supportive Housing or PSH (referred to hereafter as residents). In addition, residents' experiences accessing health services, and their sense of health activation and efforts to manage their health within PSH settings, were explored. A mixed-methods study was conducted in Southern California (October 2018-June 2019) using a validated survey and interviews with a randomly selected group of residents (n = 61) from three PSH agencies.Activation levels were measured using the Patient Activation Measure. Descriptive and univariate survey analyses were conducted. Interview data was analysed using NVivo. Two coders coded all transcripts, and team meetings were held to reach consensus. Results showed most residents were female (64%), racial and ethnic minorities (66%), on average 54-year-olds, with 37 months of PSH residency, and 43% were taking some action to manage their health (intermediate activation level). Challenges accessing care were due to breakdowns in care, unpleasant experiences with providers, low health literacy and feeling overwhelmed by co-occurring chronic conditions. Health activation related to knowing when to take care of their health on their own and when to seek care. Unique challenges emerged related to PSH, such as lack of resident control within the housing setting and limited personnel responding to health emergencies. These challenges were magnified because residents live alone, per PSH requirements.