Harry Hennessey, a respected labor leader, maritime professional, and dedicated public servant, passed away on April 7th, 2026, leaving behind a legacy defined by loyalty, service, and advocacy for working families across Long Island and the maritime industry.
Hennessey served as Secretary-Treasurer of the United Marine Division, Local 342 of the International Longshoremen’s Association (ILA), and as a Vice President and Executive Board member of the Atlantic Coast District. Over a long and distinguished career, he also worked as a Captain and Mate with Moran Towing and Transportation and spent 25 years serving the Town of Huntington as a Liaison Officer.
“The ILA is deeply saddened by the passing of our Brother Harry Hennessey,” said International ILA President Harold J. Daggett. “Harry was the epitome of a dedicated and fiercely loyal union leader who served his membership with distinction. His accomplishments on their behalf were vast and his memory will endure.”
“I am heartbroken to lose one of my most dedicated and intelligent Vice Presidents,” said Michael J. Vigneron, President of the Atlantic Coast District. “Harry was elected ACD Vice President in 2019. He was an asset to our District and our ACD membership.”
Hennessey was also closely connected to a family deeply involved in public service and local government. He was the brother-in-law of Suffolk County Deputy Presiding Officer and Legislator Jim Mazzarella, and brother to longtime Brookhaven Town and Suffolk County Republican Committee supporter Bill Hennessey, as well as former Brookhaven Town Councilman and current Judge Edward Hennessey.
In a separate statement, Suffolk County Republican Committee Chairman Jesse Garcia said, “It is with profound sadness that I share the passing of Harry Hennessey, Jr.” He added that Hennessey “dedicated his life to public service,” and extended “our deepest sympathies and condolences to the Hennessey and Mazzarella Families.”
He is survived by his wife, Maryann; daughters Siobhan and Deirdre; son-in-law Jordan; and granddaughters Shannon and Claire.
A wake will be held on Sunday, April 12, from 3:00 p.m. to 8:00 p.m. at Robertaccio Funeral Home, 495 Main Street, Center Moriches. A Funeral Mass will take place on Monday, April 13, at 10:45 a.m. at St. John the Evangelist Roman Catholic Church, 25 Ocean Avenue, Center Moriches, followed by burial services.