Dr. Fitzgerald is first named in TOS mission sixteen, "We Cannot Be," though he must also have been present to treat Acacia after the previous mission, since he greeted them with "Weren't you just here?" He appears again in mission nineteen, "Torment," when Agents Jay and Dead bring Legolas into the department (before it was common practice). Again, his reaction is telling: "DEAR GOD! Is that a CANON character?"
Dr. Fitzgerald is clearly a man who doesn't appreciate anyone making his job harder, but he always responds efficiently and to great effect. When Snowball II, a house cat, was in need of a resurrection, he complained that he was a doctor and not a veterinarian, but he revived Snowball nevertheless. He would still likely prefer that anyone seeking normal veterinary care visit the Veterinary Ward instead, though.
While "Torment" was his first named appearance, he has clearly been part of the PPC for a very long time; when Anya, part of the original agent trio, had her mind destroyed by the Mysterious Somebody in 1992, Dr. Fitzgerald handled her treatment personally, though he wasn't successful.
After the death of the Wisteria during the Black Cats' invasion in 2006, he took a position on the reshuffled Board of Department Heads, making him the only non-Flower on the Board; he is still a member as of its third incarnation.
- "We Cannot Be" (The Lord of the Rings), Agents Jay and Acacia (DMS)
- In which he is named for the first time, treating Jay's hand after she punched her console upon reading the mission report concerning Sue!Arwen.
- "Torment" (The Lord of the Rings), Agent Jay (DIC) with Agent Dead (DE)
- In which he helps prevent Legolas from fading after being assaulted by Aragorn.
- "Manic Depressive by Cliffhanger" (The Lord of the Rings), Agent Architeuthis (DoI)
- In which he examines Architeuthis and declares her fit to return to duty.
- 2008 Mary Sue Invasion, Part 7 - "Legitimate Medical Procedure" (RP)
- In which he keeps the doors to Medical open even in the face of an invasion.
- "Gingersnaps" (interlude)
- Lofty Skies, Chapter 3
- In which he appears indirectly, having been personally handling Anya's treatment. In chapter seven, he tries "desperately" to find a cure for the insanity epidemic that has swept Headquarters.
- "Origins: Prologue"
- In which he appears in his capacity as a Board member.
- "Moaning Mary, Simpsons Sue" (The Simpsons) - Agents Laburnum and Foxglove (DMS)
- In which he resurrects Snowball II, who had been killed by a Mary Sue impersonating Lisa Simpson.