In 1918 al-Hashimi was assigned as the commander of the Ottoman Fourth Army garrison in Tulkarm. That year, in the spring, he commanded Ottoman troops against the British-led offensive in Amman and al-Salt. He was wounded during these battles and sent to Damascus to recover. The British and their Arab allies in the Sharifian Army defeated the Ottomans and an armistice was concluded in October 1918. He attempted to resume his service in the Ottoman Army, but was refused because he did not apply for readmission within a year of the armistice.