His father Julius, an electrical engineer, and his mother Ethel (née Greenglass), a union organizer, were members of the Communist Party USA.

During the trial, Michael and his younger brother Robert lived first with their maternal grandmother, Tessie Greenglass, until November 1950, when she placed them in the Hebrew Children's Home in the Bronx.

Many of his articles have advocated liberal to left-wing economic policies, including, in 2005, his opposition to the Bush administration's efforts to partially privatize Social Security.

Ivy Meeropol interviewed both brothers about the Rosenberg trial and his childhood for her 2004 film Heir to an Execution, and included new comments from Michael in her 2019 documentary on Roy Cohn.

He worked for four years at John Jay College of Criminal Justice of the City University of New York teaching economics and interdisciplinary studies.

But they reiterated what they perceived to be the failures of the government prosecution:"[W]hatever atomic bomb information their father passed to the Russians was, at best, superfluous; the case was riddled with prosecutorial and judicial misconduct; their mother was convicted on flimsy evidence to place leverage on her husband, and neither deserved the death penalty.

"[6] A month later, the brothers published an op-ed in the Los Angeles Times stating that Sobell's confession revealed no detail about the theft of the atom bomb design.

They noted that the witness Ruth Greenglass' recently released grand jury testimony[7] said nothing about Ethel Rosenberg's alleged spying activities, for which the government convicted her.

Schneir said that David and / or Ruth Greenglass turned that drawing and descriptive material over to a KGB agent in December 1945 – not, as testified at the trial, to Julius Rosenberg in September 1945.

They submitted requests to President Barack Obama for a proclamation to in effect nullify the original jury verdict because of the perjuries involved in the government's case against her.