- Shannon's father, Adam Rutherford and Sarah are taken here after their accident in "Man of Science, Man of Faith". Jack chooses to save Sarah over Adam, as Adam's case is hopeless. Adam is pronounced dead at 8:15 am.
- Christian Shephard fatally botches a surgery on a woman named Beth while under the influence in "All the Best Cowboys Have Daddy Issues" and attempts to get Jack to help him cover it up.
- Angelo Busoni arrives at the Hospital to be specifically treated by Jack in "The Hunting Party". His daughter Gabriela accompanies him. Even though the situation is hopeless (the patient has an inoperable spinal tumor) Jack decides to operate anyway and the patient dies on the operating table.
- The stadium where Desmond first met Jack appears to be within driving distance of the Hospital, since Jack goes there to run the steps after his frustration with Sarah's surgery.
- Christian Shephard - Former Chief of Surgery
- Jack Shephard - Spinal Surgeon
- Head Doctor - chaired the committee looking into the death of Beth and the actions of the Shephards.
- Dr. Hamill - Present Chief of Surgery (post-island).
- Andrea - intern
- Anesthesiologist - present at Christian and Jack's surgery on Beth.
- Anesthesiologist No. 2 - present at Jack's emergency surgery on Adam Rutherford.
- Doctor (St. Sebastian) - unnamed doctor charged with telling Shannon and Sabrina about the death of Adam Rutherford.
- Intern - present at the arrival of Adam Rutherford, told Jack he couldn't intubate. Called time of death on Adam Rutherford.
- Nurse (St. Sebastian) - worked with Jack and took care of Locke
- Doctor - treated Jack for injuries sustained while rescuing a woman and her son from a crashed car (post-island).
- Dr. Leon is mentioned over a tannoy in "Through the Looking Glass, Part 1".
- Gary Nadler is mentioned by Dr. Hamill in "Through the Looking Glass, Part 1".
St. Sebastian Neurosurgery Group cited in "Something Nice Back Home":
- Dr. Jack Shephard
- Dr. Smith Sira
- Dr. .... Gardez
- Dr. .... ..evenson
- According to legend, St. Sebastian was martyred by being tied to a tree or post and shot with arrows (the arrow being his attribute). He is the patron saint of soldiers and youth, among other things. He is also a protector from the plague. (Through the Looking Glass-Enhanced transcript)
- The filming location is the St. Francis Medical Center in the Liliha district of Honolulu.[source needed]
- The exterior driveway entrance is the same location as used for the Lynford Hotel front lobby entrance in "A Tale of Two Cities". Compare with this image.
- Locke may have possibly been a patient at St. Sebastian. The nurse seen at his bedside in "Deus Ex Machina" when he donates a kidney to Anthony is later seen working with Jack in "A Tale of Two Cities".