He got into his career in the 1930s as a stringer (journalism) for Washington Post in the City of Shanghai, China. Mark Gayn also went on to write for Collier's and was arrested in the FBI raid on the offices of the Institute for Pacific Relations (IPR) Amerasia office in June 1945.
However, the charges were dropped shortly thereafter - the New York Times described him as "quickly vindicated in the courts." The State Department refused to admit his Hungarian-born wife to the United States, on the grounds of her alleged Communist sympathies, so he moved to Canada and continued his work as a foreign affairs correspondent.
He filed reports on North Korean dictator Kim Il Sung's repression and, as one of the first Western journalists admitted into China in the mid-1960s, he managed to criticize the country's Maoist regimentation.
While no known connection to the assassination of John F. Kennedy can be found, in his ebook entitled JFK Assassination Chronology, Playwright Ira David Wood 3rd thought enough of this journalist that he should be included in his work on JFK anyway.
During his life, Mark J. Gayn wrote four books - The Fight For The Pacific published in 1942, Journey From The East: An Autobiography published in 1944, Japan Diary published in 1948 and republished in 1989 and New Japan Diary which was published after his death in December 1981.
The Mark Gayn Papers - covering 50 years as a journalist - were given to the Thomas Fisher Rare Book Library, at the University of Toronto before his death in 1981. There is a typescript guide to the contents: Collection Guide to the Mark Gayn Papers (MS Col. 215), prepared by Graham S. Bradshaw. An exhibition and catalogue with material from this collection were created in 2016, Reading Revolution: Art and Literacy during China's Cultural Revolution, by Jennifer Purtle and Elizabeth Rodolfo, with contribution by Stephen Qiao
- Mark Gayn Dead at 72, Jewish Telegraphic Agency, Dec. 28, 1981
- MARK J. GAYN, 72, JOURNALIST; SPECIALIST ON FOREIGN AFFAIRS, The New York Times, Dec. 24, 1981