Born of a middle-class family, he received his commission in the Foot Artillery branch of the German army in 1885. (The foot artillery was responsible for larger caliber field guns and the fortress artillery.) He was retired in 1913 for medical reasons, having had a career of no special distinction.
As the German army expanded in the fall of 1914, he was recalled to duty as the artillery commander of the 86th Infantry Division serving on the Eastern Front. At a time when artillery preparations for offensives stretched out over many days -- sometimes over a week -- Bruchmuller advocated a 'hurricane bombardment' of several hours using a high rate of fire. He differed from his contemporaries in stressing that the bombardment's function was that of neutralizing the enemy, rather than killing him. So the bombardments which he planned were more intense than others in terms of rate of fire and made extensive use of chemical shell. He was also an early advocate of the 'creeping barrage '. His methods were first proved against the Russians at Lake Narotch in April, 1916. One of the 86th Divisions attacks in this battle netted 5,000 prisoners, many of whom had been stunned by the intensity of the bombardment. Throughout 1916 and 1917 he planned artillery preparations for all the major German offensives in the East.
In late 1917 he was transferred to France. Despite his achievements on the Eastern Front, he was still only a lieutenant colonel on temporary duty. The German preparatory bombardments which played a major role in the German successes in the spring and summer of 1918 owed much to the adoption of Bruchmüller's methods and to his planning; the opening barrage at St. Quentin on 21 March, 1918 fired 3.2 million shells and inflicted 15,000 British casualties. He came to be known as 'Durchbruchmuller', a pun combining the German word durchbruch ('breakthrough') with his name.
He retired a second time in 1919 with the rank of colonel, not having been selected for the post-war Reichswehr. He had been awarded the Pour le Merite, Germany's highest military award in 1917, one of only four senior artillery officers to receive this honor.