Feklisov worked out of the Soviet consulate office in New York City from 1940 to 1946. His supervisor was Senior NKVD Case officer Anatoli Yatskov (alias Yakovlev). Part of Feklisov's duties included recruiting espionage agent prospects from those sympathetic to the Communist Party of the United States and its auxiliary secret apparatus.
Rosenberg was among these recruits. In the period from 1943 to 1946, Feklisov reported at least 50 meetings with Rosenberg. He stated that Rosenberg provided important top secret information about electronics and helped organize an industrial espionage ring for Moscow, but "didn't understand anything about the atom bomb." Feklisov stated that Ethel Rosenberg, as a "probationer", did not meet directly with her Soviet agent handler. He also said she "had nothing to do with this" and was "completely innocent." Feklisov once wrote that Julius Rosenberg was the only agent that he viewed as a close friend. He, in response, told Feklisov that their meetings were “among the happiest moments of my life.” Feklisov was also the Case Officer for Joel Barr and Alfred Sarant, two other members of the Soviet Atomic Spy Ring. In August 1946, Feklisov returned to the USSR. By the late 1940s, he was transferred to the London Rezidentura.
Feklisov was transferred back to the United States and became the Washington, D.C. Rezident, or KGB Station Chief, from 1960 to 1964. His cover name at that time was Aleksandr Fomin. As PGU KGB Rezident, Feklisov (Fomin) proposed what became the basis for resolving the Cuban Missile Crisis: removing missiles from Cuba in exchange for a promise that the United States would not invade the island nation.
- Stanley, Alessandra (March 16, 1997). "K.G.B. Agent Plays Down Atomic Role Of Rosenbergs". Times Online. Retrieved 2008-06-24. "A retired K.G.B. colonel has for the first time disclosed his role as the human conduit between Moscow and Julius and Ethel Rosenberg, the two Americans who were executed for espionage in 1953 in one of the most notorious spy scandals of the cold war."
- "Alexander Feklisov. KGB agent who had a hand in some of the Soviet Union's most striking intelligence coups of the postwar period.". London: New York Times. November 1, 2007. Retrieved 2008-06-24.
- Weil, Martin (November 3, 2007). "Alexander Feklisov, 93; Key Soviet Spy in U.S.". Washington Post. Retrieved 2008-06-24.
- Martin, Douglas (November 1, 2007). "Aleksandr Feklisov, Spy Tied to Rosenbergs, Dies at 93". New York Times. Retrieved 2008-06-24. "Col. Aleksandr Feklisov, a Soviet spy whose long career included directing the intelligence-gathering of Julius Rosenberg, who was convicted of espionage and executed in 1953, and acting as an intermediary between the White House and the Kremlin during the 1962 Cuban missile crisis, has died. He was 93."
- Feklisov, Alexandre, The Man Behind the Rosenbergs: Memoirs of the KGB Spymaster Who Also Controlled Klaus Fuchs and Helped Resolve the Cuban Missile Crisis, New York: Enigma Books, 2001. ISBN 1-929631-08-1
- Trahair, Richard C.S. and Robert Miller, Encyclopedia of Cold War Espionage, Spies, and Secret Operations, New York: Enigma Books, 2009. ISBN 978-1-929631-75-9