After serving as a pathologist in the U.S from 1971 until 1973, he once again returned to the University of Michigan Medical School as an Assistant Professor of Pathology in 1973. He was promoted to the rank of Associate Professor in 1976 and to Professor of Pathology in 1980. From 1973 until 1983, he served as the Associate Director of the Blood Bank at the University of Michigan Hospitals. His research interests during these years revolved around the study of blood utilization in the United States and systems for reducing the use of unnecessary hospital blood bank services.

In 1982, Dr. Friedman was appointed the Director of Pathology Data Systems at the University of Michigan Hospitals, the computing support unit of the Department of Pathology, and he continues in this position today. In 1996, he was appointed as Director of Ancillary Information Systems for the University of Michigan Hospitals, which includes oversight over the radiology, pharmacy, pathology, radiation oncology, respiratory care, and home health information systems.

He is the director of a continuing education symposium on Automated Information Management in the Clinical Laboratory (AIMCL) that is devoted to the topic of laboratory information systems and automated information management in the clinical laboratories, which has been held at the University of Michigan Medical School for the last fifteen years.