During World War II, he fought in Grampa's World War II company, the Flying Hellfish, as their Radio Operator. He is also constantly the butt of several jokes by his comrades, with one particular joke involving a note saying "shoot me" being placed on his backside. He remarks that he "didn't join the unit to make friends" grudgingly after realizing the prank. He desired three chicken dinners every day after deciding to make the tontine on the Hellfish Bonanza.
Skinner's father was a soldier heading for the Korean War. Sheldon resembles his son a lot both physically and mentally, which means that Seymour Skinner inherited these qualities.
During a flashback, he can be seen sitting with his wife and son where he sings the Springfield national anthem.
- Episode – "Raging Abe Simpson and His Grumbling Grandson in "The Curse of the Flying Hellfish""
- Episode – "The Debarted" (mentioned)
- Episode – "Boy Meets Curl" (flashback)
- Episode – "The Ten-Per-Cent Solution" (sitting with Agnes in the audience of Krusty's standup act)
- Episode – "Walking Big & Tall" (flashback)
- THOH – "Treehouse of Horror XXIV " (opening sequence)
- Comic book – Simpsons Comics 144 ("War is Smelly")
| Flying Hellfish Members
|Abraham Simpson | Sheldon Skinner | Arnie Gumble | Asa Phelps | Iggy Wiggum | Milton Haas | Etch Westgrin | Griff McDonald | Charles Montgomery Burns | Commander Flanders|