BACKGROUND: There is increasing focus on designing workspaces that promote less sitting, more movement and interaction to improve physical and mental health. OBJECTIVE: This study evaluates a natural intervention of a new workplace with active design features and its relocation to a greener and open space. METHODS: An ecological model was used to understand how organisations implement change. Pre and post survey data from 221 matched cases of workers and accelerometery data (n = 50) were analysed. RESULTS: Results show a decrease in occupational sitting (-20.65 mins/workday, p = 0.001) and an increase in workplace walking (+5.61 mins/workday, p = 0.001) using survey data, and accelerometery data (occupational sitting time: –31.0 mins/workday, p = 0.035, standing time: +22.0 mins/workday, p = 0.022, stepping time: +11.0 mins/workday, p = 0.001). Improvements in interaction, musculoskeletal pain and mental health were reported. CONCLUSIONS: Application of the ecological model shows that the organisation understands how to target the built environment and social/cultural environment but not how to target behaviour change at the individual level.