Star Trek: 10 Characters That Should Teach In Starfleet Academy
2. Dax
It's not known just how long a Trill symbiont — or "short, fat snake" as the Star Trek: Deep Space Nine Series Bible also put it — can live. It's certainly in the range of hundreds of years, through several hosts. The Dax symbiont was born in 2018, meaning it would be approaching its 1200th birthday by the time of any appearance in Star Trek: Starfleet Academy.
The wealth of knowledge and experience that Dax could bring to a teaching role would be inestimable. We last saw Dax, canonically speaking, in 2375. By that point — and Jadzia, may you rest in whatever peace you can find in Sto'Vo'Kor — Ezri was the symbiont's ninth host. That's counsellor, scientist, ambassador, murderer (but excellent pianist), combat pilot, head of the Symbiosis Commission, gymnast, engineer and nail biter, and legislator/council member in the space of about 207 years. There's still over 800 to go from 2375 to the re-opening of Starfleet Academy in Kobayashi Maru.
We also know from Trials and Tribble-ations that Emony Dax once met Leonard McCoy on Earth prior to his becoming a doctor. Skip back to 2168, and we're at the year of Dax's joining to first host Lela. If we assume the Trill homeworld was aware of galactic affairs at that point, that means Dax and hosts have been witness to pretty much all of Federation history. That should qualify them to be at least the commandant, probably the superintendent, of the entire Academy!