In June 1917, the 50th Battalion was involved in the Battle of Messines; the following month, Jensen, now a corporal, was posted to a training unit in the United Kingdom. He returned to his battalion in October, and was promoted to temporary sergeant in November. In March 1918, the German Spring Offensive was launched, and Jensen fought with his battalion at Dernancourt and Villers-Bretonneux. Shortly after the fighting at Villers-Bretonneux, Jensen was on patrol when he received a severe head wound, and was evacuated to the United Kingdom, then repatriated to Australia, where he was discharged in Adelaide at the end of the war. He worked as a marine store dealer and married in 1921, but died the following year, having never fully recovered from his war wounds.