German non-profit status foundations are created through personal and corporate wealth in order to advance the common good and solve current social problems by making grants to those in need. Yet, the majority of foundations only put 5 % of their assets to use in pursuit of their mission, while 95 % of their finances are managed with the singular goal of maximizing financial value and returns. Due to the current financial crisis and fundamental demographical trends, foundations are experiencing an increasing demand for financial support, which puts pressure on them in terms of their social impact. In order to increase efficiency, foundations should seek to make investments in alignment with their charitable missions, which could be achieved through investing in a socially responsible manner. Confusion remains, however, about the extent to which German law permits foundations to consider extra-financial factors and how these match the economic goals, when making investment decisions. Based on an extensive analysis of the relevant literature and a systematic evaluation of empirical data, this paper analyses the legal considerations of the asset management as well as the theory and practice of Socially Responsible Investing (SRI) and shows that both financial and non-financial goals of the foundation can be achieved through the adoption of SRI. However, when trying to align investments and mission, the traditional separation between asset management and grant making represents the greatest challenge foundations are faced with. Therefore, this paper introduces a unified investment strategy, which offers a viable solution to meet this challenge through a conscious application of all foundation assets in pursuit of creating not simply a good grant making institution, but an institution that maximizes its full value potential.