FBI

I'm 39, but I have 4 years of 6(c) covered employment with another federal agency.  Can I still apply to be a special agent with the FBI, or is the FBI's cutoff at age 37 absolutely firm, regardless of prior covered employment?

But does that waiver include 6(c)-covered applicants who can still get 20 years of covered service in before their 57th birthdays?  After all, the "must be under 37 to apply" is driven by retirement laws.

Different agencies handle this differently.  Most do not require a waiver if you have previous covered service and can complete 20 years of service before hitting 57.  However, within the Dept. of Justice, the way the delegation of authority from the AG is worded, there is no allowance for prior service.  Take a look at Chapter 1-6 of DOJ Order 1200.1 - it's on the internet.  So, even if you have prior service, you'll need a waiver if you're over 37.  Of course, the fact you can complete the 20 years by age 57 would be good grounds for a waiver.  The only exception is if the prior service was with the FBI.