Dillon, who was the retired vice chairman and director emeritus of Hilton Hotels Corp., died peacefully Wednesday at his home in Los Angeles, a statement said.
A longtime real estate executive and confidant of retired CEO Barron Hilton, Dillon began his career as an attorney for the company's founder, Conrad Hilton.
Reflecting his close ties to the family, he served as a director of the Conrad N. Hilton Foundation since 1994, providing humanitarian aid for the world's needy, regardless of race, religion, or geography.
Local news from across Southern California
He is survived by his wife, Jenine, three sons, two daughters and seven grandchildren.
"Greg Dillon was a consummate professional in law and hotel development, and was a tremendous ambassador for our company," said Barron Hilton.
"His warmth and sincerity, and his irrepressible Irish charm, will long be remembered by our family, and by our extended hotel family around the world. He is an irreplaceable friend that I'll sorely miss."
Born in Chicago on Aug. 26, 1922, Dillon served in the Army Air Corps during World War II and later earned a law degree.
In 1950, he was hired by Hilton's law firm, and for the next 13 years he worked closely with Conrad Hilton and was instrumental in the 1954 merger with the Statler chain, and the launch of Hilton International 10 years later, the company said.
Under Barron Hilton, Dillon was involved in the acquisition and development of many Hilton properties, including the Hilton Hawaiian Village and the fee property underlying the Waldorf-Astoria.
A rosary will be held at 5 p.m. Sunday at Gates, Kingsley & Gates Funeral Chapel, 1925 Arizona Ave. in Santa Monica. A memorial Mass will be celebrated at 11 a.m. Monday at Saint Paul the Apostle Church, Ohio and Selby Avenues in Westwood.
In lieu of flowers, the family requests contributions be made to either Saint John's Health Center Foundation, 1328 22nd St., Santa Monica, CA 90404-2091, or Las Floristas, Inc., c/o Maggie Simms, 10071 Valley Spring Lane, Toluca Lake, CA 91602.