Upon graduation from the Charlotte Amalie High School in 1977, he enrolled at Tuskegee Institute (now Tuskegee University) where he received a bachelor’s degree in Plant & Soil Science. Petersen later earned a master’s degree in Horticultural Science from Oklahoma State University and a doctorate in Horticulture with an emphasis in Plant Genetics from the University of Minnesota along with a minor degree in Plant Pathology.
Petersen returned to the territory in 1989 and commenced employment at the Cooperative Extension Service of the University of the Virgin Islands where he served as an Extension Agent. He worked for a total of twenty years at the UVI Cooperative Extension Service where he has also served as District Supervisor and Assistant Director for the St. Thomas-St. John District. During his career Dr. Petersen has served as a member of the local School to Work/Career Council, the Sustainable Agriculture Program State coordinator for the USVI, past president, vice president and recording secretary of the VI Resource Conservation and Development Council, and executive member of the local chapter of the Caribbean Food Crops Society. He also served as past secretary, vice president and president of the Southern Association of State Departments of Agriculture. Louis is currently the president of the USVI Agriculture and Food Fair Board of Directors.
From 1995 to 1999 Petersen was appointed as Assistant Commissioner of the Virgin Islands Department of Agriculture, and from 2007 – 2014 as Commissioner. Since May 2023, Petersen has been serving as Commissioner Nominee of the Virgin Islands Department of Agriculture. His vision for the department is to increase its professional capacity and resources through partnerships and strategic initiatives to enhance its delivery of services and programs to the farming community.
Petersen is married to Algem Petersen and together they have one son, Dwayne.