For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty while serving with the 3d Battalion, 23d Marines, 4th Marine Division, in combat against enemy Japanese forces during the seizure of Iwo Jima in the Volcano Island, 26 February 1945. Promptly destroying a stubborn 20mm. antiaircraft gun and its crew after assuming the duties of a bazooka man who had been killed, Pfc. Jacobson waged a relentless battle as his unit fought desperately toward the summit of Hill 382 in an effort to penetrate the heart of Japanese cross-island defense. Employing his weapon with ready accuracy when his platoon was halted by overwhelming enemy fire on 26 February, he first destroyed 2 hostile machinegun positions, then attacked a large blockhouse, completely neutralizing the fortification before dispatching the 5-man crew of a second pillbox and exploding the installation with a terrific demolitions blast. Moving steadily forward, he wiped out an earth-covered rifle emplacement and, confronted by a cluster of similar emplacements which constituted the perimeter of enemy defenses in his assigned sector, fearlessly advanced, quickly reduced all 6 positions to a shambles, killed 10 of the enemy, and enabled our forces to occupy the strong point. Determined to widen the breach thus forced, he volunteered his services to an adjacent assault company, neutralized a pillbox holding up its advance, opened fire on a Japanese tank pouring a steady stream of bullets on 1 of our supporting tanks, and smashed the enemy tank's gun turret in a brief but furious action culminating in a single-handed assault against still another blockhouse and the subsequent neutralization of its firepower. By his dauntless skill and valor, Pfc. Jacobson destroyed a total of 16 enemy positions and annihilated approximately 75 Japanese, thereby contributing essentially to the success of his division's operations against this fanatically defended outpost of the Japanese Empire. His gallant conduct in the face of tremendous odds enhanced and sustained the highest traditions of the U.S. Naval Service.