First responders, such as paramedics and firefighters, encounter duty-related traumatic exposures, which can lead to post-traumatic stress (PTS). Although social support protects against PTS, we know little about how first responders’ families, spouses/partners, friends, and care-partners (i.e., ‘trusted others’) provide social support. This narrative review explores support behaviors, coping strategies, and resources trusted others use to support first responders. A structured literature search yielded 24 articles. We used House’s (1981) conceptual framework to inform our analysis. We identified three main themes: providing support, finding support, and support needs. Additionally, we describe trusted others’ self-reported preparedness, coping strategies, and barriers to providing social support. We found that trusted others provided different types of support: (a) emotional (fostering a safe space, giving autonomy over recovery, facilitating coping mechanisms, prioritizing first responders’ emotional needs); (b) instrumental (prioritizing first responders’ practical needs, handling household tasks, supporting recovery); (c) appraisal (active monitoring, verbal reassurance, positive reframing), and (d) informational (seeking informal learning). In their role, trusted others sought formal (organizational) and informal (peer and personal) support and resources, alongside intrapersonal and interpersonal coping strategies. Identified barriers include inadequate communication skills, maladaptive coping, and disempowering beliefs. Thus, we offer practical, treatment, and social support recommendations.