Mr. Zwack cut an unusual figure in the diplomatic corps when he arrived in Washington in 1990. The Washington Post once described him as “one of the most colorful among the ambassadors in Washington” and later, after an unbecoming departure, “one of the most controversial.”
A celebrity in his native country, Mr. Zwack managed in the late 1980s to reclaim control of his family’s famed Zwack distillery — the producer of Unicum, an 84 proof bombshell sometimes called the Hungarian national shot — after four decades of communist government ownership.
Western news media hailed him at the time as apparently the first businessman in the nationalized economies of Eastern Europe to achieve such a feat. There were calls in Hungary for him to run for president.
Beyond those distinctions, Mr. Zwack was a naturalized U.S. citizen and therefore an unlikely candidate for a foreign ambassadorship. He and his family had fled to the United States in 1948, after the government nationalized the distillery. They left behind a bogus recipe for Unicum, a concoction made from 40 herbs and roots that was created, according to family lore, in the late 1700s by a Zwack ancestor.
During communist control in Hungary, the government-owned Zwack distillery produced a version of Unicum that was not quite right. Mr. Zwack’s father had tucked the bona fide formula in his back pocket when he escaped from Budapest to Vienna, hidden under an oil drum on a Soviet truck. Mr. Zwack later helped store the recipe — split into four parts for added security, according to news accounts — in safe-deposit boxes at four New York banks.
He had arrived at Ellis Island stripped of his considerable family wealth. He sold vacuum cleaners before finding work, first in New York and later in Chicago, in the wine-and-spirits import-export trade.
In 1971, he moved to Italy, where he joined a relative who had been producing small quantities of Unicum — the real thing — for connoisseurs around the world who did not buy from the communist-run distillery.
Then, in 1988, the reform-minded “goulash communists” invited Mr. Zwack to return to Hungary. He agreed and, over time, reclaimed control of the distillery. Today it is known as Zwack Unicum, a publicly listed company owned by the Zwack family with several partners.
“People think I showed faith in Hungary when not too many others did,” he told the New York Times in 1989. “They had been fed this picture of a fat capitalist who smoked cigars and beat up the workers, and they saw me, a skinny guy who doesn’t smoke, wears beat-up clothes and behaves more like the workers than the Communist bosses did.”