He became famous for his roles in the television series LA Law - Star lawyers, tricks, processes as Douglas Brackman and Dharma & Greg as Larry Finklestein. For the former he received a Golden Globe and an Emmy nomination.
In the 1970s and early 1980s Rachins wrote screenplays for television series such as Knight Rider, Hart to Hart, The Fall Guy and Quincy.
He is married to actress Joanna Frank, with whom he has a son. Rachins is a member of Mensa International, an association for people with high IQs.