Purpose To examine feasibility and acceptability of providing stepped collaborative care case management targeting posttraumatic stress disorder (PTSD) and pain symptoms after major traumatic injury. Materials and methods Participants were major trauma survivors in Victoria, Australia, at risk of persistent pain or PTSD with high baseline symptoms. Participants were block-randomized, stratified by compensation-status, to the usual care (n = 15) or intervention (n = 17) group (46% of eligible patients). The intervention was adapted from existing stepped collaborative care interventions with input from interdisciplinary experts and people with lived experience in trauma and disability. The proactive case management intervention targeted PTSD and pain management for 6-months using motivational interviewing, cognitive behavioral therapy strategies, and collaborative care. Qualitative interviews explored intervention acceptability. Results Intervention participants received a median of 7 h case manager contact and reported that they valued the supportive and non-judgmental listening, and timely access to effective strategies, resources, and treatments post-injury from the case manager. Participants reported few disadvantages from participation, and positive impacts on symptoms and recovery outcomes consistent with the reduction in PTSD and pain symptoms measured at 1-, 3- and 6-months. Conclusions Stepped collaborative care was low-cost, feasible, and acceptable to people at risk of PTSD or pain after major trauma. IMPLICATIONS FOR REHABILITATION After hospitalization for injury, people can experience difficulty accessing timely support to manage posttraumatic stress, pain and other concerns. Stepped case management-based interventions that provide individualized support and collaborative care have reduced posttraumatic stress symptom severity for patients admitted to American trauma centers. We showed that this model of care could be adapted to target pain and mental health in the trauma system in Victoria, Australia. The intervention was low cost, acceptable and highly valued by most participants who perceived that it helped them use strategies to better manage post-traumatic symptoms, and to access clinicians and treatments relevant to their needs.