Epler, who had one son Zbigniew (born 1919), was raised in an affluent family: his father Edward was a railroad engineer and deputy mayor of the city of Lwów. In 1909, he graduated from Classical Gymnasium in Chyrów, and began studies at Lwów University. In 1912, Epler was drafted into the Austro-Hungarian Army, serving at XI Artillery Brigade, and graduating from School of Reserve Officers. On May 1, 1915, he was promoted to Subcolonel (podporucznik). During World War I, he fought on the Italian Front, and in 1918, he completed artillery course for officers, which took place at Trento.
After the collapse of Austria-Hungary, Epler returned to former Austrian Galicia and joined the newly created Polish Army. In mid-November 1918, he was named commandant of an artillery battery of 1st Kraków Field Artillery Regiment. Together with the regiment, he fought in the Polish–Ukrainian War and Polish–Soviet War. In 1920, he was transferred to 3rd Legions Field Artillery Regiment.
After the Polish–Soviet War, Epler completed a military training course in Toruń, and was promoted to major. In 1922–1929, he served as artillery officer in the garrison of Zamość, where 3rd Legions Infantry Division was stationed. He was highly praised by General Stanislaw Kwasniewski, who at that time commanded the 3rd Division.
On December 4, 1929, Epler was named commandant of 28th Field Artillery Regiment, which was stationed in Zajezierze near Dęblin. He remained there until October 1935, and during his service at Zajezierze, he was popular among soldiers due to his organizational abilities. From October 1935 until the Invasion of Poland, Epler served in 20th Infantry Division in Baranowicze.
In early September 1939, Epler took command of Reserve Center of 20th Infantry at Slonim. In a matter of few days, he managed to create the so-called Kobryn Group, with the strength of a regular infantry division. His unit, renamed into 60th Infantry Division, joined Independent Operational Group Polesie (General Franciszek Kleeberg), and fought in the final battles of the September Campaign, including Battle of Kock (1939).
On October 6, 1939, Epler was taken prisoner by the Germans, who allowed him to keep his officer's sword. He was taken to a temporary camp at Dęblin, and then transferred to Radom. With help of local boy scouts, Epler managed to escape, and fled to Kraków, where he joined conspiratorial Organization of White Eagle, using the pseudonym Kobylanski. To escape arrest, he decided to flee to Hungary. In December 1940 he reached Egypt, and after the war settled in London, where he died on October 24, 1965.
Epler wrote the book Last Polish soldier of the 1939 campaign. It was published first in 1942 in Tel Aviv, and reprinted in Poland in 1989. On October 28, 1994, President Lech Wałęsa posthumously promoted him to Generał brygady.Knight's Cross of the Virtuti Militari
Silver Cross of the Virtuti Militari
Gold Cross of the Virtuti Militari
Officer's Cross of the Order of Polonia Restituta
Cross of Valour (Poland) (four times)
Gold Cross of Merit (Poland) (on November 10, 1938)