Vallario was born in New York to first-generation immigrants from Piedmont, Italy. As a child, Vallario was friends with future Gambino boss John Gotti. During the 1970's, Vallorio joined the Gambino family as a crew member for Gravano in the Bensonhurst and Red Hook sections of Brooklyn. Vallario's illegal activities included loansharking, illegal gambling, bookmaking, and labor racketeering. Vallario was a close criminal associate of Frank Fappiano, Edward Garafola, Thomas Carbonaro, and Joseph D'Angelo. When Salvatore Gravano later became a government witness, he refused to testify against Vallario.
In 1985, Gotti murdered boss Paul Castellano and underboss Thomas Bilotti to take over the Gambino family. Gravano then became consigliere and Vallario took over Gravano's crew. Vallario reportedly became one of Gotti's top aides. In the late 1980's and early 1990's, Vallario became a prominent figure in the construction industry and enjoyed major influence over the New York City labor unions.
On March 8th 1988 Vallario took part in the murder of gambino crime family member Liborio Milito. Milito was called to a meeting at Louis Vallario's bar to discuss the murder of a Gambino associate. Gene Gotti, John Carneglia, Louis Vallario and Arnold Squitieri were present at the meeting, as was Salvatore Gravano. at 7pm Milito walked into Vallario's bar Gene Gotti, Arnold Squitieri and Salvatore Gravano were playing a card game at the table. John Carneglia was watching TV on the couch and Louis Vallario was behind the bar. Milito asked Vallario for some coffee and While Milito was drinking some espresso, Carneglia got up from the couch and came up behind Milito with a .380 calibre handgun w/silencer. He fired a bullet into the back of Louie Milito's head. Milito fell off his barstool and lay faceup on the floor, Carneglia bent over him and shot him under his chin. Milito's death was similar to the murder of Capo Robert DiBernardo as they both asked for coffee and were shot in the head. Milito's body was loaded into a car by Carneglia and Squitieri they drove off and dumped the body it has never been found.
In 1991, dozens of members of the family were indicted and sent to prison on Racketeer Influenced and Corrupt Organizations Act (RICO) charges, such as racketeering, extortion, loansharking, illegal gambling, conspiracy and murder for hire. Salvatore Gravano eventually turned state's evidence, as John Gotti and Consigliere Frank Locascio were sentenced to life imprisonment in 1992, the same time as Vallario was charged with racketeering.
In 1996, Vallario was promoted to the Gambino "Ruling Panel" with Capos Steven Grammauta and Michael DiLeonardo, John D'Amico and Peter Gotti. John Gotti created the panel to assist his son John A. "Junior" Gotti, as acting boss. Vallario sat on the panel until 2002.
Convictions and prison
In April 2001, Vallario was indicted in a corruption case against officials of Service Employees International Union Local 32B-32J. Prosecutors charged that corrupt members of this union enriched themselves through no-show jobs. Vallario pleaded guilty and was sentenced to three years probation.
In 2002, Vallario was indicted for murder, extortion, loansharking, bribery and illegal gambling. In April 2004, Vallario pleaded guilty to the 1989 murder of Frederick Weiss. A recycling executive and former city editor of the Staten Island Advance, Weiss was involved with the Gambino family in a landfill scheme. Boss John Gotti ordered Vallario to kill Weiss because Gotti feared Weiss might become a government witness. Vallario shot Weiss to death outside Weiss's home on Staten Island. Vallario was sentenced to 13 years in federal prison. He served his time at Fort Dix Federal Correctional Institution (FCI) in Fort Dix, New Jersey and was released on October 15, 2013.