Climate change effects lead to a transformation of our environment. The building sector is considered to have the greatest potential in the clean energy transition. However, general consensus of climate change definitions, communication and cooperation on climate change knowledge and perspectives is underdeveloped in the industry. A review of previous studies shows that the construction industry is known to take a reactive stance rather than proactive towards climate change action. The aim of the study is to describe how the implementation of circular principles as part of climate change action, is managed by a construction company, and to explore how this can be done proactively. Through desk research and interviews with representatives of the case firm this description is developed. The findings show that both a proactive strategy by the company as individual proactive behavior by employees can have a big impact on the performance regarding circular activities. People who are showing proactive circular behavior need to be supported and given recognition by the organization. The other way around, these people can triumph and establish organization-wide implementation of their initiatives through issue selling and perseverance. People who are not showing proactive circular behavior will need to be made aware, informed and motivated to conduct circular practices.