Newly installed CEOs have the advantage of starting fresh when they join an organization that needs deep-rooted change. But typically they are also cast in the role of "corporate savior" and expected to demonstrate rapid improvements in performance—even when market conditions are tough and they are struggling to familiarize themselves with the details of the business. Recent history is littered with the reputations of people and organizations that failed the test.

In fact, few chief executives can claim to have successfully transformed even one large, foundering organization. Yet Corrado Passera has already transformed two.

Passera joined Carlo De Benedetti's business empire in 1985 and thereafter served as CEO and COO of the holding company CIR (Compagnie Industriali Riunite), deputy chairman of Credito Romagnolo, COO of Arnoldo Mondadori Editore, deputy chairman and CEO of Gruppo Espresso-Repubblica, and managing director and co-CEO of Olivetti. Although he forged his reputation at these businesses from 1985 to 1995, nothing could have fully prepared him for the challenge he faced in 1998, when the Italian government asked him to take over the reins at Poste Italiane. This state-owned postal system—then a byword for Italian...