The Federal Judicial Center, on its Web site, says he was not. Some readers, objecting to the description of as the first Hispanic nominee to the high court, say Cardozo was Hispanic.
According to Harvard professor and Cardozo biographer Andrew L. Kaufman, "it's all in the context."
Cardozo was nominated to the court by President Herbert Hoover in 1932. He was a member of a prominent family of Sephardic Jews who claim Portuguese heritage.
That's where the certainty ends.
Some definitions of Hispanic include Portugal and Portuguese-speaking cultures; others don't.
Kaufman said Cardozo's ancestors came to the Americans colonies in the 1700s from England and Holland, but no one has ever firmly established that the family's roots were, in fact, in Portugal.
Cardozo himself was proud of his heritage, Kaufman said, but he probably never had occasion to consider whether he was Hispanic.
"It just wasn't a term in common political parlance, or social parlance, at the time," Kaufman said.
"I think it would be a surprise to most Hispanics to learn that Justice Cardozo was the first Hispanic and I think it would be a surprise to most people at to learn it," said Michael Herz, vice dean of the Benjamin N. Cardozo School of Law at New York's Yeshiva University.
By another measure, though, Cardozo was an "ethnic pick," Herz said.
Cardozo had three things going against him — his religion, his address and his Democratic Party affiliation, Herz said.
In an era when there was a Jewish seat, a Catholic seat and regional seats on the court, there already was a Jewish justice, Louis Brandeis, and a New Yorker serving. Cardozo also was a Democrat, while Hoover was a Republican.
Yet Hoover nominated Cardozo and the Senate confirmed him unanimously.