 In the latter year Rennie was hired at the "New York Tribune" as a general assignment reporter, often covering police cases and ship arrivals of notables such as Hollywood, Broadway, or sports stars.He was promoted to assistant city editor in 1922.Rennie became a naturalized U.S. citizen on 16 June 1922,

Taking a leave of absence from the "Tribune" in August 1922, Rennie sailed to Europe to settle a maternal aunt's estate, thereafter touring Ireland, England, Scotland, and France (including places significant to his wartime military service) until the end of 1922.