Born in Montreal, Quebec, Peuchen was the son of a railroad contractor; his maternal grandfather managed the London, Brighton and South Coast Railway. He was educated in private schools.
In 1888, he entered military life and became a lieutenant of The Queen's Own Rifles of Canada. Peuchen moved up the ranks, and in 1911, was marshalling officer at the coronation of George V.
In 1897, Peuchen perfected plans for extracting useful chemicals from coarse hardwoods and waste woods, the principal products being acetic acid, acetate of lime, acetone, methanol, and formaldehyde. The acids were used by dyeing industries, formaldehyde was used by wheat growers in Canada, and acetone was used to manufacture high explosives like cordite.
Peuchen subsequently became president of Standard Chemical, Iron & Lumber Company of Canada, Ltd. The company had many plants and facilities in Canada, as well as refineries located in Canada (Montreal), France, Germany, and the UK (London). Because some company facilities were located abroad, Peuchen often traveled to Europe by ship.
Peuchen owned a yacht named Vreda, which crossed the Atlantic under its own canvas. Additionally, he was, for a time, Vice-Commodore and Rear-Commodore of the Royal Canadian Yacht Club.
Peuchen boarded Titanic at Southampton, on 10 April 1912, as a first-class passenger on his 40th transatlantic voyage. He reportedly was concerned that Captain Smith was in command, because he thought Smith was a poor commander and too old.
On the night Titanic sank, Peuchen saw that Lifeboat No. 6, which contained Quartermaster Robert Hichens and Molly Brown, was poorly manned and came forward to Second Officer Lightoller, saying he was a yachtsman. Captain Smith was standing nearby and suggested Peuchen go down to the Promenade Deck, so he could break a window and climb into Lifeboat No. 6. Lightoller replied, however, that Peuchen could slide down the ropes to enter the boat if he was as good a sailor as he claimed. Peuchen then took a rope, swung off the ship, and climbed hand-under-hand down to Lifeboat No. 6. He was the only male passenger that Lightoller would allow into a lifeboat that night. He later claimed he did not realize Titanic was doomed until he viewed the ship from the lifeboat.
Because Peuchen was a military officer, he came under scrutiny for allowing Hichens to prevent the boat's occupants from going back for survivors and for tolerating the verbal abuse Hichens reportedly gave. Peuchen was also criticized for exaggerating his own role and for not recognizing the pivotal role Margaret (Mrs J J) Brown played in leading the lifeboat's occupants in rowing and in raising morale. It is possible that Peuchen, as a yachtsman, may have thought that second-guessing an officer in charge would encourage mutiny.
Peuchen publicly blasted Captain Smith and the crew of Titanic, criticizing their seamanship as substandard; however, his official testimony at the United States Senate inquiry into the disaster was tempered somewhat from interviews he gave in the days after the rescue.
In 1987, Peuchen's wallet was recovered from the area around the remains of Titanic; streetcar tickets, a traveler's cheque, and his calling card were found inside.
In Toronto, Peuchen was deemed a coward, largely because of his self-serving attitude, and speculation gathered that his expected promotion to Lieutenant-Colonel in The Queen's Own Rifles would not be awarded. Despite the publicity, the promotion was made on May 21, 1912; he also received the Volunteer Officers' Decoration. When World War I began, Peuchen retired from Standard Chemical to command the Home Battalion of the Queen's Own Rifles.
In later years Peuchen's social standing in Canadian society had slipped greatly, as a man who survived both the sinking of Titanic and World War I. He made bad investments and lost much of his finances during the 1920s.
He died in Toronto on 7 December 1929 in his 71st year. His body was buried in Toronto's Mount Pleasant cemetery.Robert Ayres in A Night to Remember (1958 film)