PURPOSE: People with moderate-to-severe traumatic brain injury (TBI) are frequently inactive with increased risk of higher rates of chronic health conditions, mortality and economic burden than peers without TBI. Understanding how this population experience physical activity participation may help us develop better pathways and supports to community-based physical activity. MATERIALS AND METHODS: Using an interpretive description approach, we conducted a secondary analysis of focus group and interview data. Themes were generated in two stages of inductive coding and refined in a workshop by the author team which comprised multidisciplinary researchers, clinicians and people with lived experience of moderate-to-severe TBI. RESULTS: Twenty-two people with moderate-to-severe TBI took part. They experienced physical activity in diverse and often changing ways, reflecting the numerous, powerful tensions that people with TBI are striving to navigate. Four themes were identified: 1. What is my new normal?, 2. Invisible injuries, hidden needs, 3. The long road back to physical activity, and 4. Expanding horizons. CONCLUSIONS: People with moderate-to-severe TBI have to work hard to be physically active. Results indicate that physical activity promotion should include person-centred information and support, appropriate community-based options that go beyond rehabilitation, and insurance funding that recognises the value of life-long physical activity.