No age limit. I've personally seen people get hired into the public service in their 40s and 50s. The requirements are pretty straightforward: be a PR or citizen, meet whatever education/experience the posting asks for, and pass a security clearance.
Big caveat for 2026 though: the federal government has been going through major budget cuts and workforce reductions since 2024. Hiring is way slower than it used to be. So the odds of getting in right now are honestly lower than they were a few years ago. That doesn't mean you shouldn't try, but you should be realistic about timelines.
In terms of what's still hiring even during the cuts, IT and finance tend to be more resilient since those skills are always in demand. CRA also tends to hire in waves for processing positions.
The pay is pretty decent once you're in. A CR-04 clerk starts around $56K, a PM-02 program officer around $64K, and IT-02 (where most tech people enter) starts at $86K. Plus the pension is legitimately amazing. But getting through the door right now is the hard part.
If you want to see what different positions pay, fedpay.ca has all the rates from the collective agreements. Useful for setting realistic expectations before you start applying.