Giuseppe Magliocco was born in Portella di Mare, a frazione in the comune of Misilmeri, in the province of Palermo, in Sicily. Magliocco's nickname "Joe Malayak" came from the word Maluk, which meant "ruler". Despite weighing over 300 pounds, Magliocco was described as being very energetic and decisive in his work and physical gestures, someone who exuded danger and confidence.
Magliocco lived on a six-acre waterfront estate in East Islip, New York. He was the silent partner in a liquor company, Alpine Wine and Liquor, and a linen company, Arrow Linen Supply. In 1963, it was suspected that Magliocco was using his clout to force bars and restaurants to buy from both companies. According to Joseph Bonanno, Magliocco was an excellent Italian chef and loved to eat.
Magliocco's son Ambrose Magliocco was a capo. Magliocco's second cousin and brother-in-law was mob boss Joseph Profaci, founder of the Profaci crime family. Magliocco was an in-law of consigliere and underboss Salvatore Mussachio, related by marriage to Buffalo crime family boss Stefano Magaddino, and uncle to the wife of Bonanno crime family founder Joseph Bonanno.
As a young man, Magliocco became involved in illegal gambling and union racketeering.
On December 5, 1928, Magliocco and Profaci attended a meeting of New York mobsters at the Statler Hotel in Cleveland, Ohio. The main topic was dividing the Brooklyn territory of the recently murdered boss Salvatore D'Aquila without causing a gang war. By the end of the meeting, Profaci had received a share of the open territory, and named Magliocco as his second-in-command—a post he would hold for the next 34 years. When the Cleveland Police raided the meeting, Magliocco was briefly detained on an illegal weapons charge.
In 1931, the Castellammarese War began in New York between two powerful Italian-American gangs. Both Profaci and Magliocco attempted to stay neutral during this conflict. By the end of 1931, the war was over and the New York gangs were divided into five crime families supervised by a Mafia Commission. Profaci and Magliocco were confirmed as boss and underboss, respectively, of what was now known as the Profaci crime family.
In 1957, Magliocco was arrested with 60 other mobsters who were attending the Apalachin Conference, a national mob meeting in Apalachin, New York. On January 13, 1960, Magliocco and 21 others were convicted of conspiracy and he was sentenced to five years in prison. However, on November 28, 1960, a United States Court of Appeals overturned the verdicts.
During this same time period, conflict was growing in the Profaci family. Many Profaci crew members were dissatisfied with the share of family profits that they were forced to give to Profaci. The most dissatisfied group was the Gallo faction led by Joe Gallo with his brothers Larry Gallo and Albert Gallo. The final insult came when Profaci ordered the killing of Frank Abbatemarco, a Gallo associate, then took all of Abbbatemarco's rackets away from the Gallos.
In February 1961, the Gallos kidnapped Magliocco, Frank Persico, and then-capo Joseph Colombo. They also tried to get Profaci, but he managed to escape to Florida. After several weeks of negotiation, the Gallos reached an agreement with Profaci on an improved financial arrangement and released the three men.
However, six months later, Profaci reneged on the deal and war broke out between the Gallos and the Profaci family.
On June 6, 1962, Profaci died of liver cancer and Magliocco became the family boss. However, the Mafia Commission did not endorse him as the new family leader.
Afraid that the other New York families viewed him as weak, Magliocco increased the tempo of violence against the Gallo faction. In turn, car bombs, drive-by shootings, and other murder attempts were made against Magliocco men such as Carmine Persico and his enforcer, Hugh McIntosh. In 1963, with the jailing of Gallo and several associates, the hostilities temporarily ended.
In 1963, Joseph Bonanno, the head of the Bonanno crime family, made plans to assassinate several rivals on the Mafia Commission—bosses Tommy Lucchese, Carlo Gambino, and Stefano Magaddino. Bonanno sought Magliocco's support, and Magliocco readily agreed. Not only was he chafing at being denied a seat on the Commission, but Bonanno and Profaci had been close allies for over 30 years prior to Profaci's death. Bonanno's audacious goal was to take over the National Crime Syndicate and make Magliocco his right hand man.
Magliocco was assigned the task of killing Lucchese and Gambino, and gave the contract to one of his top hit men, Joe Colombo. However, the opportunistic Colombo revealed the plot to its targets. The other bosses quickly realized that Magliocco could not have planned this himself. Remembering how close Bonanno was with Magliocco (and before him, Profaci), as well as their close ties through marriages, the other bosses concluded Bonanno was the real mastermind.
The Commission now summoned Bonanno and Magliocco to explain themselves. Fearing for his life, Bonanno went into hiding in Arizona, leaving Magliocco to deal with the Commission. Badly shaken and in failing health, Magliocco confessed his role in the plot. The Commission spared Magliocco's life, but forced him to retire as Profaci family boss and pay a $50,000 fine. As a reward for turning on his boss, Colombo was awarded the Profaci family.
On December 28, 1963, Joseph Magliocco died of a heart attack at Good Samaritan Hospital Medical Center in West Islip, New York. Magliocco is buried in Saint Charles Cemetery in Farmingdale, New York.
In 1969, the authorities exhumed Magliocco's body to determine if he had been poisoned. This action was taken based on FBI phone tapings in which DeCavalcante crime family boss Sam DeCavalcante suggested that Joseph Bonanno poisoned Magliocco. However, no traces of poison were found in the body and it was re-interred at Saint Charles.