William Kincaid was a physiotherapist based out of a California hospital.
- William is of Old German origin, and its meaning is "will, helmet, protection".
- When he was attempting to motivate Locke, he said a phrase very similar to John's credo: "Don't tell me what I can't do".
John, you fell eight stories and survived, okay? I don't wanna hear about what you can't do.
- A Dr. Kincaid is also mentioned in the episode "Exposé", when Paulo reads the description of the director he and Nikki had just killed. One of the shows it was said the director had been the mastermind of was "Dr. Kincaid Esquire".
- The casting call described him as "Clif - Strong physique, sympathetic and likeable. Male - African-American"