Background: Major trauma is a growing health issue in Aotearoa New Zealand, with 2,661 cases recorded in 2022–2023. Trauma survivors face a high risk of developing post-traumatic stress disorder (PTSD), with international prevalence estimates of 23–29%. PTSD is associated with increased complications, prolonged hospital stays, and delayed return to work, yet routine screening is not standard practice. This study explored the feasibility and acceptability of introducing a PTSD screening tool into trauma care, guided by the Consolidated Framework for Implementation Research (CFIR) and the Equity-based Framework for Implementation Research (EquIR), with explicit attention to cultural safety and alignment with Te Tiriti o Waitangi principles. Case: A mixed-methods design was used. Stakeholders included doctors, clinical nurse specialists, resident medical officers, psychiatrists, people with lived experience, and whānau. Quantitative data were collected via an online Likert-scale questionnaire assessing relevance, feasibility, and inner-setting readiness. Qualitative data were obtained through semi-structured interviews using cognitive interviewing techniques to explore comprehension, judgement, and response to the proposed screening tool. Interviews were analysed thematically and mapped to CFIR domains. Conclusions: All participants agreed PTSD is relevant to trauma care, and 97% reported willingness to use the tool if appropriate training were provided. Five themes emerged: language and cultural safety; appropriateness and timing of screening; training and role clarity; integration into existing workflows; and resourcing and follow-up pathways. Māori and Pasifika participants emphasised culturally safe practice, Whānau Ora navigation, and community co-design. Integration into the tertiary survey was identified as key to feasibility. While concerns were raised regarding limited follow-up capacity, participants supported PTSD screening, recognising its potential to improve outcomes for patients and whānau.