After completing his B.A. at Colby College, his M.A.T. at Brown University, and his M.A. at SUNY-Albany, David Erdmann began his independent school career as head of the history department at Trinity-Pawling School. From there he went to The Albany Academy where his positions included chair of the history department, director of college counseling, head of the upper school, and interim headmaster. Erdmann then became dean of admission at Rensselaer Polytechnic Institute and, since 1985, he was the dean of admission and enrollment at Rollins College.

At Rollins his responsibilities included admission, financial aid, retention, and institutional research. Since leaving Albany Academy in 1980, Erdmann continued his involvement with independent schools as an enrollment and search consultant and presenter for regional and national independent school organizations. He founded and directed The Essex Institute for Independent School Enrollment Management, was a trustee at Trinity Preparatory School in Winter Park, Florida and served as a member of the NAIS Financial Aid Services Task Force.

David passed away in October of 2013, while pursuing his passion, fly fishing, on his favorite pond in Winter Park. He was 69 years old. He was a loving husband to his wife of 48 years, Sue, and proud father of daughter Lindsay, a Rollins graduate.