Nearest I can tell, the term "staff engineer" was an unusual one in use at certain shops, and was popularized big time around 2020. That looks about right. It

Nearest I can tell, the term "staff engineer" was an unusual one in use at certain shops, and was popularized big time around 2020. That looks about right. It came along with the increases in hiring and compensation in parts of the industry, the resulting employee's market, the resulting desire to show a long technical career ladder with many more steps than we used to have, and the resulting devaluation of the "senior" title that was once a big deal. For employers to show how much they value the more capable people who used to be "senior" and can take on roles like technical leadership or cross-team architecture, the employers have now adopted titles like staff, senior staff, principal, fellow, etc. Naturally those positions attract interest for the same reason that "senior" used to. It's the level where a person typically becomes self-sufficient and able to work on more demanding initiatives under only broad direction. It's also the level where those with an interest in technical leadership become capable enough to run larger teams or groups effectively and probably limit their personal technical contributions to more strategic activities or surgical interventions. I'm not sure how much has really changed apart from the titles, though. There has always been a qualitative shift in emphasis around that level of experience and ability for developers, whatever we choose to call it. And the responsibility and authority you have in your role, often reflected in compensation and how colleagues relate to you, has always said more about your real seniority than any formal job title.