There are two components to GS, grade and step. Step is based on time, grade is based on position. It's also possible that this person came out as a GS-14 rather than a lower GS-12 or GS-13 due to the attempt at merit based pay (NSPS) that was canceled 3 (4?) years back. Their pay may have been improved via merit increases under NSPS and GS-14 might have been the closest equivalent to their pay or they could have been miscoded as a GS-14 equivalent and it wasn't corrected. Most of these were left as-is rather than fighting to "demote" them to avoid the hassle. Especially since most of them would be retiring within 5 years or so, or would have been promoted to that same level in the near future. Rather than demote them they just won't get the promotion just a lateral move.
GS grades tend to correspond to scope of work, degree of education required and scope of responsibilities. If the work doesn't require a college degree, don't expect anything above GS-9, and probably no better than GS-7. If it's "business ops" that requires a degree but has limited responsibilities you might be a GS-11, engineers are (after their "apprenticeship" period) between GS-11 and GS-13 (essentially, education + depth of knowledge, most GS-13 engineers will be SMEs, subject matter experts). Supervisors will typically be one grade above those they supervise, maybe on par with SMEs, with a typical minimum grade of GS-11. So a supervisor in charge of 40 engineers might be a GS-13, their boss would be a GS-14 and that persons boss a GS-15.
GS grades tend to correspond to scope of work, degree of education required and scope of responsibilities. If the work doesn't require a college degree, don't expect anything above GS-9, and probably no better than GS-7. If it's "business ops" that requires a degree but has limited responsibilities you might be a GS-11, engineers are (after their "apprenticeship" period) between GS-11 and GS-13 (essentially, education + depth of knowledge, most GS-13 engineers will be SMEs, subject matter experts). Supervisors will typically be one grade above those they supervise, maybe on par with SMEs, with a typical minimum grade of GS-11. So a supervisor in charge of 40 engineers might be a GS-13, their boss would be a GS-14 and that persons boss a GS-15.