The Core Principles are a list of characteristics that all Lumon Industries employees and followers of Kier Eagan are expected to demonstrate. These principles are intended to unite and inspire those who adhere to them, and to lead them to become more industrious workers and better people.

There are nine Core Principles. They are:

1. Vision
2. Verve
3. Wit
4. Cheer
5. Humility
6. Benevolence
7. Nimbleness
8. Probity
9. Wiles

The Core Principles feature prominently in documents intended for severed employees. These include the Compliance Handbook and The Macrodata Refiner’s Orientation Booklet. The principles are designed to intertwine and overlap, as they should all be considered together instead of as separate. There is an emphasis on good social skills, because employees are considered not just a team, but a community or family.

In Half Loop, Irving mentions that a fun fact about him is he knows all nine Core Principles. When Milchick asks him which is his favorite, Irving responds, “All nine. But today, I think I’d say, “cheer”.”