|Behind the scenes|
|First episode||Full Moon, Saturday Night|
|Last episode||On the Beach|
William Swift, known as Wild Willy, is a fictional doctor from the medical drama ER.
He temporary stepped in for David Morgenstern as Chief of Emergency Medicine in the first season. He and Dr. Greene initially do not get along, as Mark is trying to cope with the death of a pregnant patient. Dr. Swift has him present the case at the next Mortality & Morbidity, which ultimately helps Mark through his guilt.