Alphonse was 22, single and living in Mildmay, ON when he enlisted on 2 July 1940 at a Kitchener, ON recruiting depot from the Royal Canadian Regiment Regimental Depot from London. He had been working with a local lumber company for four years as a sawyer at that time and stated during the enlistment procedure that he wanted to be a machinist.
Within a week, Alphonse was sent to the No 1 Infantry Recruit Training Center in Camp Borden, ON. After completing his recruit training, he proceeded to No 10 Infantry Training Centre, also in Camp Borden on 2 July 1941 - a full year after he had enlisted. Alphonse completed three months of infantry training and then embarked for the United Kingdom on 5 October 1941 as a reinforcement.
Upon arrival in the United Kingdom, Alphonse was assigned to No 1 Canadian Infantry Holding Unit but was soon transferred to No 2 (later renamed No 6) Construction Company, Royal Canadian Engineers, on 17 November 1941. This company was part of No 1 Canadian Engineer Holding Unit and worked on construction projects while training tradesmen. Alphonse was qualified as a Concretor Group “B” on 16 December 1941. He remained with No 6 Construction Company until March 1944 and worked on construction projects in the UK throughout. Alphonse married Margaret Keating of Brixton in London on 7 August 1943.
On 18 March 1944, Alphonse was transferred to the 11th Field Company while the company was in its final preparations for the invasion of the Continent. He embarked for France with his company on 5 July and, as an indication of the activity in Normandy even one month after D-Day, he did not disembark in France until four days later. less than three weeks later, his wife gave birth to a baby girl, Jackie, who was born on 23 July 1944. He never got to see his daughter.
The company soon started obstacle clearance and bridge construction in the Caen area. After Caen, the company supported the Allied advance in France and then through Belgium, Holland, and eventually into Germany. Among its operations, the company participated in the Battle of Falaise, The Scheldt, The Rhineland, and The Rhine. By the end of February 1944, the unit had arrived in Germany as the Allied forces continued to push back the enemy.
On 16 March, the 11th Field Company began to check a stretch of ground near Cleve, Germany for mines in order to make the area safe for the Queen's Own Cameron Highlanders of Canada. By the next evening, the mine-clearing parties had found a number of German Riegelmine 43 anti-tank mines that they safely lifted and stored in two dumps. At 1300 hrs the next day, Sapper Brown was part of Lieutenant O. H. Taylor’s party of nine that set out to destroy the mines in the two dumps. A half-hour later, something went terribly wrong. There was a terrific explosion and all were killed. No evidence was ever found to indicate why the tragedy had occurred.
Sapper Alfonse Anthony John Steffler was Killed in Action on 18 March 1945 at age 27. He was buried in the Canadian Temporary Cemetery at Bedberg, Germany and was later moved to his final resting place in the Nijmegen Canadian Military Cemetery - now named the Groesbeek Canadian War Cemetery.