[2][3] He defected on September 5, 1945, three days after the end of World War II, with 109 documents on the USSR's espionage activities in the West.

[5] Granville Hicks described Gouzenko's actions as having "awakened the people of North America to the magnitude and the danger of Soviet espionage".

[9] Gouzenko spent a lot of time in the Lenin Library, where he prepared for admission to the university and then entered the Moscow Architectural Institute.

[12] On September 5, 1945, three days after the end of World War II, the 26-year-old Gouzenko walked out of the embassy carrying a briefcase with Soviet code books and decryption materials, a total of 109 documents.

When he returned later, the editor-in-chief was no longer at work, and the paper's night editor did not venture to take responsibility,[14] and suggested he go to the Department of Justice but nobody was on duty when he arrived there.

[15] The next morning, September 6, he returned with his wife and child to the Department of Justice and asked to see the minister; after waiting several hours, he was denied an appointment.

Shortly before midnight, four men from the Soviet Embassy (Pavlov, Rogov, Angelov and Farafontov) broke into an apartment on Somerset Street looking for Gouzenko and his documents.

Although the RCMP expressed interest in Gouzenko, Prime Minister of Canada William Lyon Mackenzie King initially wanted nothing to do with him.

[18] Even with Gouzenko in hiding and under RCMP protection, King reportedly[citation needed] pushed for a diplomatic solution to avoid upsetting the Soviet Union, still a wartime ally and ostensible friend.

Documents reveal that King, then 70 and weary from six years of war leadership, was aghast when Norman Robertson, his undersecretary for external affairs, and his assistant, H.H.

Gouzenko and his wife Svetlana, they told him, had appeared at the office of Justice Minister Louis St. Laurent with documents unmasking Soviet perfidy on Canadian soil.

[22] The evidence provided by Gouzenko led to the arrest of a number of suspects,[21] including Agatha Chapman, whose apartment at 282 Somerset Street West was a favourite evening rendezvous.

"[23] A Royal Commission of Inquiry to investigate espionage, headed by Justices Robert Taschereau and Roy Kellock, was conducted into the Gouzenko Affair and his evidence of a Soviet spy ring in Canada.

A clerk at External Affairs, a Canadian Army captain, and a radar engineer working at the National Research Council were arrested for espionage.

In the United States the FBI tracked down a Soviet spy, Ignacy Witczak, at the University of Southern California (USC) in Los Angeles.

[30] He remained in the public eye, writing two books, This Was My Choice, a non-fiction account of his defection, and the novel The Fall of a Titan, which won a Governor General's Award in 1954.

In June 2003, the city of Ottawa[33] and in April 2004, the Canadian federal government[34] put up memorial plaques in Dundonald Park commemorating the Soviet defector.

The story of the process of lobbying the two levels of government to unveil the historic plaques is told in the book Remembering Gouzenko: The Struggle to Honour a Cold War Hero by Andrew Kavchak (2019).

[35] Another film version of the Gouzenko Affair was made as Operation Manhunt in 1954, directed by Jack Alexander, with screenplay by Paul Monash, and starring Harry Townes and Irja Jensen, released by United Artists.

"Rubess, effectively abetted by Oliver Dennis's fumbling performance in the lead role, portrays Gouzenko as a hapless bungler who barely succeeds in rifling the telltale documents," Toronto Star theatre critic Vit Wagner wrote in a review of the production.