Contributing to sustainable development remains a challenge for most private companies and many scholars have attempted to identify factors that can facilitate the adaptation process that is needed for effective sustainable practices (hereafter referred to as corporate social responsibility or CSR). This PhD thesis examines the role of learning and human resource development in the CSR adaption process. The key message of this thesis is two-fold. Firstly, because CSR managers are the ones who actually manage the adaptation process they can play a crucial role in this process if they possess the right individual competencies. In order to develop these individual competencies, CSR managers should take ownership of their learning process and seek opportunities to learn with and from others. Secondly, adequate leadership and connecting with external parties are of particular importance to the CSR adaptation process. We hope that by developing the relevant CSR-related competencies, CSR managers will effectively manage the CSR adaptation process and more ambitious sustainability challenges are successfully addressed by private companies.