rank-and-file employee; ordinary staff member
Refers to a regular employee without a managerial title; often contrasted with 管理職 (managerial positions).
He's still a rank-and-file employee, but he's capable.
I was promoted from an ordinary staff member to section chief.
He was promoted from a rank-and-file employee to section chief.
Five years after joining the company, I'm still just a rank-and-file employee.
She works as a rank-and-file employee.