Yes, around 100,000 German Jews served in the Imperial German Army during the First World War. Approximately 12,000 were killed, of which about 3000 have known graves. While Jews didn’t receive the level of persecution during the First World War that came with the rise of Nazism in the 1930’s, they were still subjected to anti-semitism from within the military and without from German society.
Jews serving within the military were initially barred from becoming officers due to their faith but as the war continued and vacant officer positions needed to be filled by experienced soldiers, Jews were promoted to commissioned ranks but only in the Reserves, they were still barred from holding commissioned ranks in the regular army.
In 1916, a Judenzählung (Jewish census) was held in Germany to determine the extent to which German Jews were avoiding military service. The census returned a result that discredited such claims but the results were quashed and never publicly released. Anti-Semitic papers released their own results that claimed Jews were not contributing to the war effort while Jewish groups conducted their own census and tried to releases their findings but were prevented from doing so by the Minister of Defence who defended the claims of the anti-Semitic papers.
Many German Jews viewed their contribution to the First World War as a means of proving their loyalty which had long been questioned by Germans to their German homeland. Some Jews also viewed the war in the east as a means of liberating their Jewish neighbours from the anti-semitism that was rife throughout Tsarist Russia.
Of the 100,000 Jews that fought in the German Army, some 18,000 were awarded commendations in the form of the Iron Cross. After the war, German veterans working in the public service were initially protected from the anti-Jewish laws passed by the Nazi regime. This was promoted by the German President, Paul von Hindenburg, who had served in the military as a senior commander during the war. These protections were eventually stripped and German-Jewish veterans were subjected to the same level of persecution by the Nazi’s as the rest of the Jewish population. This included transportation to the concentration camps and murder. The Nazi party attempted to expunge any record of Jewish contributions to the war effort during the First World War but post-World War Two efforts have restored our knowledge of those efforts and the German Bundeswehr actively promotes the efforts of German Jews currently serving.