He directed several high-profile prosecutions of Communists, including the cases of Alger Hiss, William Remington, Abraham Brothman, and Julius and Ethel Rosenberg.

[1][2] He was born on September 3, 1905, one of four sons of Louis and Michakin Saypol, an American Jewish family, on the Lower East Side of Manhattan.

[1][2][3] He attended night classes at Brooklyn Law School, where he met fellow student Adele B. Kaplan; they married in September 1925.

[2][1] Irving Saypol led the prosecution of several members of the Communist Party of the United States (CPUSA), including Eugene Dennis, William Z.

Foster, John Gates, Robert G. Thompson, Gus Hall, William Remington, Abraham Brothman, and Miriam Moskowitz.

"[7] From 1950 to 1951 Saypol served as Chief Prosecutor for the federal government in the espionage case against Julius and Ethel Rosenberg and Morton Sobell.

[1] At his funeral Charles D. Breitel, Chief Judge of the New York State Court of Appeals, said "We on the bench knew that he would handle a case with integrity.