Upon completing a year of internship and 14 months of internal medicine residency at Loma Linda University (LLU), Dr. Rentschler joined the U.S. Army Medical Corps and served as a general medical officer for two years. He then went on to do a fellowship in developmental therapeutics at MD Anderson Hospital.
Dr. Rentschler worked as a full-time faculty member of the medical oncology department at LLU from 1976 to 1990 and then as associate clinical professor of medicine from 1990 to 2005. He also served as chief of oncology and hematology at Beaver Medical Group for 15 years.
Dr. Rentschler has been a member of numerous committees and has served in leadership positions for many of them. He retired from clinical practice in 2005 and worked as a part-time physician recruiting for Beaver Medical Group until 2016. He and his wife, Judy, currently live in Yucaipa, and they have three children, Brian, Gina, and Scott.