In 1993, the Italian authorities captured Mr. Riina in Sicily’s capital, Palermo, and judges ultimately gave him 26 life sentences. He spent a good deal of the next quarter-century in isolation, with little time outside his cell in Milan.

The Italian justice minister, Andrea Orlando, allowed family members to visit Mr. Riina in the hospital on Thursday, his birthday. He had four children, one of whom, Salvo, wrote on Facebook, “You’re not Totò Riina to me, you’re just my dad.” Another of Mr. Riina’s sons is in prison for committing four murders.

Complete information on his survivors was not immediately available.

Mr. Riina, who was rife with nicknames — he was also called U Curtu, or Shorty, because of his 5-foot-2 height — came from Corleone, a town in the Sicilian hinterland made famous as the birthplace of the fictional character Vito Corleone in the “Godfather” movies.

But Mr. Riina’s butchery was all too real. After serving time in his youth for killing a man in an argument, he became a soldier under the Mafia boss Luciano Leggio. He rose through the ranks, eliminating competitors and at times running his gang in hiding, though apparently always from Sicily. By the early 1980s, Mr. Riina had solidified his dominance over the island and its global criminal activities.