Out of the dozens of American spies active from the 1930s-onward, the overwhelming majority were Jewish-by-race. Only a few — e.g. Whitaker Chambers, Alger Hiss, Elizabeth Bentley — were non-Jews.
Kindly note that this list below is just the tip of the Jewish spy iceberg. There were scores of top-echelon Jewish spies in America from the 1930s-onward, actively spying for the Soviet communists. In fact, we own a large list of those spies. So why not list them all here? Some were never convicted in a court of law, some were apparently-Jewish but not provably-Jewish, etc. As we get more concrete information about Jewish spies, we will list more names.
Julius Rosenberg; electrical engineer; transferred U.S. atomic secrets to the Soviets, sentenced to death and executed in June 1953.
Ethel Greenglass Rosenberg; wife of Julius; transferred U.S. atomic secrets to the Soviets, sentenced to death and executed in 1953.
David Greenglass: brother of Ethel Rosenberg; aided the Rosenbergs; was a Los Alamos machinist; passed drawings of atomic implosion lens to Harry Gold.
Morton Sobell; former employee of the Navy’s Bureau of Ordnance; radar engineer and former classmate of Rosenberg.
J. Robert Oppenheimer; top U.S. nuclear scientist; was in charge of the Manhattan Project; gave the Soviets atomic secrets.
Leo Szilard; worked with Oppenheimer on the Manhattan Project.
Bruno Pontecorvo; born in Italy; emigrated to Oklahoma in 1940.
Morris Cohen [aka Peter Kroger]; spy recruiter; assisted the Rosenbergs; entered U.S. Army in 1942.
Lona Cohen; [aka Kroger]; wife of Morris Cohen.
Robert Soblen; fled to Israel; committed suicide while being extradited back to America in 1962.
Jack Soble; head of a U.S. spy ring which included ‘Agent Frost’; members of the ring
were indicted/arrested in 1957.
Victor Perlo; the CPUSA’s [American Communist party] official economist; was on the War
Lee Pressman; Congress of Industrial Organizations [CIO] lawyer; Communist party member.
Jacob Albam; an associate of Jack Soble.
Nathan Gregory Silvermaster; see this powerful quote from a February 25, 2000 FBI public information press release, re: its public Electronic Reading Room: “Nathan Silvermaster Group — 1,951 pages; Nathan Silvermaster was a leader of a Soviet espionage ring. This espionage investigation from 1945 to 1959 uncovered Soviet placed agents working within the U.S. Government. The case – titled Gregory, using the middle name of Silvermaster – exposed 27 individuals in the Silvermaster ring who gathered information from at least six Federal agencies to turn over to the Soviets. No indictments for espionage were returned against any subjects in the Gregory case by any Grand Jury; however, a Grand Jury did return an indictment against Alger Hiss for perjury.” That Mr. Silvermaster oversaw 27 spies — and that the FBI says so regardless of no indictments — is significant.
V. J. Jerome [aka Isaac Romaine]; the theoretician of the CPUSA.
Alexander Trachtenberg; member, CPUSA.
Israel Amter; a CPUSA leader.
“Gus Hall” [Arvo K. Halberg]; U.S. Communist Party chairman; defendant in Foley
Square trial of American Communists.
Philip Bart; general manager of the Daily Worker newspaper.
“Carl Winter” [Philip Carl Weissberg]; defendant in Foley Square trial of American Communists.
Joel Barr; pal of Julius Rosenberg; electrical engineer; worked on military radar at the U.S. Army Signal Corps lab at Fort Monmouth; recruited by Rosenberg; fled to Czechoslovakia, he assumed fake identity.
Harry Dexter White [real name Weiss]; Deputy Secretary of the Treasury under Henry Morgenthau; helped create the World Bank.
Alfred Sarant; pal of Barr; electrical engineer; worked on military radar at the U.S. Army
Signal Corps lab at Fort Monmouth; recruited by Rosenberg; fled to Czechoslovakia and
assumed fake identity.
Harry Gold [real name Goldodnitsky]; chemist; part of 1940s Fuchs-Gold spy ring.
Theodore Hall [real name Hallsberg, also claimed Holtzberg]; worked with Enrico Fermi and J. Robert Oppenheimer; “was the first to provide the Soviets with the crucial information that helped them build the bomb.” 
Yakov [Jacob] Golos; chief organizer of spying action through the American Communist party.
Armand Hammer; millionaire; Communist; head of Occidental Petroleum; one of the world’s only millionaire/Communists.
Samuel Dickstein; U.S. Congressman from New York. Recently-released Soviet records revealed his spying.
Jonathan Pollard; U.S. Navy intelligence analyst; passed classified material to Israel — where he is a national hero due to his spying actions.