Lieutenant Sabourin joined the Canadian Army, serving in the Canadian Intelligence Corps. Because of his training, skills, and his fluency in both the French language and the English language, he was recruited into the Special Operations Executive.
From the London, England base, he was parachuted into occupied France where he worked with the French Resistance but was captured by the Gestapo with members of the Robert Benoist group and shipped to Buchenwald concentration camp on August 27, 1944.
Twenty-one-year-old Roméo Sabourin was executed by the Nazis on September 14, 1944 along with two other Canadian SOE agents, Frank Pickersgill and John Kenneth Macalister.
Lieutenant Sabourin is honored on the Groesbeek Memorial in the Groesbeek Canadian War Cemetery in the Netherlands. As one of the SOE agents who died for the liberation of France, Lieutenant Sabourin is listed on the "Roll of Honor" on the Valençay SOE Memorial in the town of Valençay, in the Indre departément.