Ash was born in to a family of interpreters, a job that on his polyglot world includes aspects of being an advocate or secretary. His family did work for the spacefaring aliens who colonized their world and thus he ended up learning to make himself useful in their engineering department.
Some years later as the aliens left he joined with Smoke and Ember to make an engineering partnership, changing his name to Ash in the process. The three of them joined Starfleet under special, experimental arrangement where they share the post of Chief Engineer between themselves, arranging their sleeping schedule so there is always one of them on duty.
Because there aren’t enough felinoid fan species already.