The purpose of this study is to clarify the tendencies and characteristics of Compassion Satisfaction and Compassion Fatigue among social work practitioners supporting the economically disadvantaged, and to examine the effects of Trauma-Informed Care (TIC) and Workplace Social Capital on Compassion Satisfaction and Compassion Fatigue. A web-based survey of workers at local welfare offices, councils of social welfare, NPOs, etc. was conducted. Overall, Compassion Satisfaction was significantly higher and Compassion Fatigue was significantly lower among workers with a high score in TIC measures. The most influential factors of TIC were “positive coping” and “self-efficacy at work.” It was also suggested that Compassion Fatigue may increase when low TIC workers are placed in a work environment with few peers and few trusting or mutually beneficial interactions with superiors. It was concluded that in order to improve workers’ support quality and health, it is worthwhile to consider the introduction of TIC, as an approach which helps to understand and respond to the effects of trauma on oneself and others.