Sebastiano DiGaetano was born in the town of Castellammare del Golfo in Sicily in c. 1862, to Arcangelo DiGaetano and Angela DiBenedetto. He first arrived in the United States on October 24, 1898, with his wife and daughter joining him in 1901. By 1908 the DiGaetano family had moved from Manhattan to the Williamsburgsection of Brooklyn, with Sebastiano becoming a barber. DiGaetano's daughter, Angelina, married Joseph Ruffino, who was arrested for burglary in 1913 along with future mafia boss Joe Masseria.
DiGaetano is believed to have become the boss of the Williamsburg-centered mafia sometime in 1909 or 1910. DiGaetano first came to the attention of authorities in December 1910, when he was arrested under suspicion of orchestrating the kidnappings of eight-year-old Giuseppe Longo and seven-year-old Michael Rizzo for ransom. The charges were later dropped due to lack of evidence. A few months later, Salvatore Clemente, a Secret Service informer who was a counterfeiter in the Morello gang was summoned to a meeting with DiGaetano. DiGaetano told Clemente to refrain from his counterfeiting activities until another mafioso, named Carmelo Codaro, who was suspected of disloyalty was "disposed of." DiGaetano was able to dictate orders to a member of a different mafia crime family because he had been made a temporary capo dei capi, or "Boss of bosses", after the previous one, Giuseppe Morello, had been imprisoned in Atlanta on counterfeiting charges. DiGaetano had assumed that role due to his relative weakness as a crime boss. Morello had been hoping that would allow him to continue to dominate the New York mafia from prison. However, the arrangement had collapsed by 1912 which led to Salvatore D'Aquila being selected as a permanent replacement as capo dei capi. In March 1912, DiGaetano stepped down as boss of his crime family and was soon replaced by Nicolo Schiro. Clemente claimed that DiGaetano was stepping down because he had "lost his nerve". Shortly after he stepped down as boss, DiGaetano disappeared; some researchers believe he and his wife may have returned to Italy.
