Lifer

They know what a clever lad he is; he'll be a lifer. They'll make the Artful nothing less than a lifer.

Source: wiktionary

"[…]The Top's not a lifer; he's a career Marine. Lifers are a breed. A lifer is anybody who abuses authority he doesn't deserve to have. There are plenty of civilian lifers."

Source: wiktionary

LRRP planned to become “career” Army, i.e., a lifer, you kept that quiet. Basic LRRP theology said the Army sucked and that philosophy kept one from going crazy because, at the bottom, nothing about the war seemed to make sense anyway. The LRRP's considered a lifer a loser. Being a lifer implied one had no other options available. Every LRRP had his own stories about back home: about family, friends, lovers, opportunities, dreams and a future. These were mostly fantasy, but […]

Source: wiktionary

In the early years of EMS, the term lifer was an entitlement pinned to anyone who had worked the road for ten years or longer with no real plans of seeking a replacement trade. It was a term that was generally delivered in a respectful and lighthearted teasing manner by someone who by all definitions could have easily been described as a lifer himself—with the exception of one drawback. So far, the crews didn't know anyone who had worked in the field for ten years, much less longer […]

Source: wiktionary