Buck Bokai (sp?) is recognised very much as a celebrity.
...By all of two people in the Federation, it seems - Stubbs and Sisko.
Even today, obscurity can carry the appearance of popularity, as a "personal cult" can be effectively constructed by a single person - the fan, not the target of idolatry. However, it doesn't appear as if either Stubbs or Sisko would have actively marketed the virtues of their hero or his obscure field of proficiency to the rest of the world(s). They just found these personally intriguing. I don't think this quite meets the criteria of "popular", as the population involved is so insignificant. (Well, insignificantly small, at any rate.)