On 3 October 1918, the 5th Brigade—of which the 18th Battalion was part—became engaged in its last battle of the First World War when breaching the Hindenburg Line close to Beaurevoir and Montbrehain. While taking part in this battle, Maxwell was a member of the attacking party along the Beaurevoir-Fonsomme line when he performed the acts for which he was awarded the Victoria Cross.
Early in the advance, Maxwell's company commander was severely wounded, resulting in Maxwell assuming control. Reaching the German barbwire defences under intense machine-gun fire, the company suffered heavy casualties, including all of the officers except Maxwell. Pushing forward alone through a narrow passageway in the wire, Maxwell captured the most dangerous machine gun, killed three Germans and took another four as prisoners; thereby enabling the company to move through the wire and reach their objective Shortly afterwards, it was noticed that the company on their left flank was held up and failing to advance. Gathering a party of men, Maxwell led the group in an attempt to attack the German force from the rear. They soon came under heavy machine gun fire, and, single-handedly, Maxwell dashed forward and attacked the foremost gun. Firing his revolver, he managed to shoot five of the crew and silence the gun.
Later in the advance, Maxwell learnt from an English-speaking prisoner that a group of Germans in the adjacent post wished to surrender, but were afraid to give themselves up. Accompanied by two privates and the prisoner—who was to act as an interpreter—Maxwell approached the post. The three Australians, however, were immediately surrounded by a group of twenty German soldiers and disarmed. They seemed set to become prisoners themselves, before an artillery barrage fell on the position. Taking advantage of the resulting confusion, Maxwell pulled out a concealed revolver and shot two of the Germans before escaping with his men under heavy rifle fire; one of the privates was subsequently wounded. Organising a party of men, he immediately attacked and captured the post.
The full citation for Maxwell's Victoria Cross appeared in a supplement to the London Gazette on 6 January 1919, it read:
War Office, 6th January, 1919
His Majesty the KING has been graciously pleased to approve of the award of the Victoria Cross to the undermentioned Officers, Non-commissioned Officers and Men: —
Lt. Joseph Maxwell, M.C., D.C.M., 18th Bn., A.I.F.
For most conspicuous bravery and leadership in attack on the Beaurevoir-Fonsomme line near Estrees, North of St. Quentin, on the 3rd October, 1918.
His company commander was severely wounded early in the advance, and Lt. Maxwell at once took charge. The enemy wire when reached under intense fire was found to be exceptionally strong and closely supported by machine guns, whereupon Lt. Maxwell pushed forward single-handed through the wire and captured the most dangerous gun, killing three and capturing four enemy. He thus enabled his company to penetrate the wire and reach the objective. Later, he again dashed forward and silenced, single-handed, a gun which was holding up a flank company. Subsequently, when with two men only he attempted to capture a strong party of the enemy, he handled a most involved situation very skilfully, and it was due to his resource that he and his comrades escaped.
Throughout the day Lt. Maxwell set a high example of personal bravery, coupled with excellent judgment and quick decision.