Scleroderma, particularly systemic sclerosis, is a chronic illness that affects a person's physical, emotional, psychosocial, and spiritual dimensions. To investigate self-care deficits, health behaviours, and trajectory management of Thai people with systemic sclerosis, an exploratory case study method was used through interviews and patient records. Self-care deficit nursing theory and the chronic illness trajectory framework guided the research. Twelve patients with systemic sclerosis were purposively recruited at a hospital clinic in the northeastern region of Thailand. Thai people living with systemic sclerosis developed specific self-care agencies in each of 3 identified trajectory patterns to improve their health and well-being. By applying the theory and framework that guided the research, nurses can promote self-care behaviours and recognize situations along an illness trajectory that require intervention and management. The results extend the understanding of how people live and cope with systemic sclerosis.