He is a past president of the Central Conference of American Rabbis (CCAR) and Hebrew Union College-Jewish Institute of Religion.
In 2000, Zimmerman was suspended from the CCAR after an inquiry regarding inappropriate sexual conduct revealed a pattern of predatory behavior, including fondling and kissing a teenager.
Zimmerman served as the senior rabbi of Central Synagogue in New York City from 1972–1985 and Temple Emanu-El in Dallas, Texas.
After leaving HUC, Zimmerman worked as executive vice president of the popular Birthright Israel program.
[8][9] Zimmerman was suspended by the Central Conference of American Rabbis (CCAR) in 2000 after what was described as inappropriate “personal relationships” that violated ethical codes.