Portrayed by Mark Harmon (1983–1986)
Handsome plastic surgeon Robert "Bobby" Caldwell arrived at St. Eligius at the beginning of season 2, and it was later revealed that he had been having an ongoing affair with hospital administrator Joan Halloran. Towards the end of that season, Bobby ended the relationship because he felt it was largely based on superficial factors and he wanted a more intimate relationship. However, he ultimately became much more superficial and promiscuous (going against typical character development), and ended up having a series of flings and one-night stands (one of whom was an unstable woman who slashed his face with a razor blade, leaving him with a large scar). Shortly after this, Bobby was diagnosed with HIV (the first instance of an ongoing character contracting the virus on US network television, and one of the earliest depictions of a heterosexual character contracting the virus). When his HIV status became known to others, Bobby was told he could no longer be involved in patient care at the hospital, though he initially refused to leave. Devastated at his diagnosis and the effect it had on his career, he almost committed suicide, but was interrupted by a neighbor's child knocking at his door requesting his help. He then decided to go on with his life, but he left St. Eligius, and Boston, towards the end of season 4, to work part-time in an AIDS hospice on the West Coast. Bobby's former St. Eligius colleagues and friends were informed of his death during a season 6 episode; several of them held a memorial for him in St. Eligius's chapel.