Another sharp guy IMO was Giovanni (John) Tartamella, who served as an important capo, and later, as the consigliere to boss Joe Bonanno. Throughout all his years as a mafioso, Tartamella, as best as can be determined, had no police record to speak of (or a minor one, at best, that was dismissed and buried.) Yet, he operated almost uninterrupted in labor union rackets for over fifty years as one of Bonanno's closest aides and advisors.
That to me, is called success.