Dr. Wagemaker is a board-certified psychiatrist. He taught in the Department of Psychiatry at the University of Louisville from 1975 to 1986. While there, he was the medical director of Central State Hospital, Louisville, KY. While at the University of Louisville, his research in schizophrenia was funded by the National Institutes of Mental Health. He was also involved in research in psychopharmacology. Later, Dr. Wagemaker joined the faculty of the Department of Psychiatry at the University of Florida's teaching hospital, Shands Jacksonville, where he was director of inpatient psychiatry.

At the present time, Dr. Wagemaker is in private practice in Ponte Vedra Beach, Florida, and is involved in research with children suffering from autism.

He is also the Director of Ponte Vedra Publishing, which publishes mental health books and mental disorder educational videos.