In research conducted for my PhD on CSR, I identified four types of Corporate Sustainability and Responsibility (CSR) Change Agents: Experts, Facilitators, Catalysts and Activists.

Each type represents a constellation of attributes. It is expected that any individual CSR change agent will embody elements of all of these types, but that the relative influence of each type will differ per individual.

Hence, the dominant type can be thought of as a centre of gravity for each CSR change agent's work, i.e. the mode of operating in which they feel most comfortable, fulfilled or satisfied.

I have written a short (1 page) article - part of the CSR Inspiration series - which summarises the model. It is available as a Pdf download on:
http://www.waynevisser.com/article_waynevisser_csr_change_agents.pdf.