Krämer has written extensively in the field of environmental law, being the author of around 20 books and manuals, as well as approximately 150 articles on European Union environmental law. In addition to being a visiting professor at University College London, Krämer is also a professor of European and German environmental law at the University of Bremen. He also teaches at the College of Europe in Bruges and many other universities. Currently, he serves as a senior advisor at ClientEarth and is a member of the Advisory Board on Justice and the Environment.
Ludwig Krämer is a former head of the Legal Unit of the Directorate-General for Environment of the European Commission from 1987 to 1994, after which he moved to lead the Waste Management Unit. In 2001, Krämer became the head of the Environmental Management Unit, a position he held until his retirement in 2004.