Jack has to come to terms with his family when his brother Eddie comes by. Meanwhile, Liz has to fire some of her employees, and Tracy tries to find a new religion in order to preempt legal troubles.
This episode contains the following tropes:
- The Alcoholic: The Donaghys toast to their father for an hour straight, and when Eddie tells them he's been sober for seven months, they take it as a joke.
- Bait-and-Switch: Eddie mentions that there's some controversy around the Catholic Church lately...because of The Da Vinci Code.
- Breaking Bad News Gently: Jack shows Liz an adorable video of a panda cub sneezing before he tells her that she'll need to fire 10% of her staff.
- Chuck Cunningham Syndrome: Neither Eddie nor any of Jack's other siblings show up again, and later episodes imply that Jack is an only child. Jack's father is also implied to be long absent or dead in later episodes, clashing with what we see here. This may cross over with Early-Installment Weirdness.
- Con Man: Both Jack's father and brother.
- Church of Happyology: Spoofed here with the Church of Practicology.
- Double-Meaning Title: "Fighting Irish" is both a common phrase to describe the Irish and a description of what the Irish-American Donaghy family ends up doing.
- Drunk with Power: It doesn't take long for Liz to start abusing her power to fire people.
- Fire and Brimstone Hell: Kenneth's preacher gives his sermons about this. Kenneth is enchanted, while Tracy is unnerved.
- Fun with Acronyms: Eddie asks for checks to be made out to Chicago All Saints Hospital, or "C.A.S.H." This is how Liz finds out that he's a con man.
- George Jetson Job Security: Liz unilaterally fires the Other Liz, and then the rest of the accounting department when they protest. Jack rehires them almost immediately.
- Kicked Upstairs: Jack gives Other Liz a promotion, requiring her to transfer to GE Corporate Headquarters in Connecticut and allowing Liz a chance with her soon-to-be-ex boyfriend.
- Meet My Good Friends Lefty and Righty: Jack, his father, and Eddie all name their fists: Jack's are "St. Patrick" and "St. Michael", Jack's father names his "Tip O'Neill" and "Bobby Sands", and Eddie's are "Bono" and "Sandra Day O'Connor".
- Not What It Looks Like: Liz finally gets in the elevator with her crush, who's now single...only for Pete to enter the elevator and talks about his problem with his wife in a way that makes it sound like he and Liz are having an affair.
- Removing the Rival: Liz tries to fire Other Liz in order to break her up with her boyfriend (who Liz has a crush on).
- Repetitive Name: Katherine Catherine Donaghy.
- Sibling Rivalry: Jack and Eddie do not remotely get along, although their father's death (well, "death") brings them closer together.
- Too Spicy for Yog-Sothoth: Tracy proves too crazy for even the Practicologists.
- Yes-Man: The entire TGS team becomes this to Liz when they hear word that they might get fired.
- You Say Tomato: Jack pronounces his last name with a hard G ("Don-a-ghee"), while his brother Eddie pronounces it with a soft G ("Don-a-hee"). Meanwhile, Jack's father pronounced it as "Don-a-fee".
