Felix Fechenbach had become an active official in the labour movement. During this time he went to continuation school to extend his elementary knowledge.

On 30th August 1914, he received a letter of conscription to active service. In February 1915 he was wounded whilst out on patrol. In March he wrote cheerfully from the military hospital in Pforzheim: "Now I only have a shot wound, a bladder infection, two boils and six endocrine glands - otherwise I feel fine". He was awarded the Iron Cross, Class II.