Madden served in the New Guinea and Bougainville campaigns in the latter stages of World War II, and after service with the British Commonwealth Occupation Force in Japan, he returned to civilian life in 1947.

He enlisted for service in the Korean War in 1950 and joined the 3rd Battalion, Royal Australian Regiment (3 RAR), in Korea in November of that year as a private.

According to the historian Craig Blanch, from the time of his capture Madden obstinately resisted his captors, verbally abused them when they beat him, and maintained an unbroken spirit while assisting fellow prisoners.

The beatings included rifle butt strikes to the chest which broke several ribs; he was further punished through restriction of rations, and his physical condition deteriorated.

Many of his fellow prisoners contributed witness statements to support the recommendation that he be posthumously awarded the George Cross, which was announced in December 1955 and presented to his sister the following year.

[3] Bill, as he was known, was working as a fruiterer's assistant when he was mobilised for service in World War II with the Militia on 26 May 1942 at Morisset, near Newcastle, north of Sydney.

[4] Nicknamed "Slim" due to his lean build,[1] Madden initially saw service with the 8th Field Ambulance in the Territory of New Guinea during the eponymous campaign of the Pacific War,[2] and contracted malaria.

[1] On 19 August 1950, Madden enlisted as a private in the special force that was being raised to serve in the Korean War, which had broken out two months earlier.

[1] On the day Madden joined the battalion near Pakchon, 3 RAR had its first engagement with Chinese forces, which had recently entered the war in support of North Korea.

[6] On 25 January 1951, the United Nations forces launched an offensive aimed at reaching the Han River, and they were able to advance 60 km (37 mi) in two weeks.

In April, the objective of Operation Rugged was the "Kansas Line", running west of the Imjin River about 45 km (28 mi) north of Seoul.

This was initially a precautionary measure, but by evening disorganised and panicking groups of ROK soldiers were moving south through the brigade position.

During the fighting withdrawal, Madden struggled with the effects of his concussion, and when urged to move by his platoon sergeant, he told him he was "stuffed" and needed a rest but would "catch up".

Madden highly valued his World War II service medal ribbons, and according to the historian Craig Blanch, when the Chinese took them he responded with unbridled verbal abuse.

[10] The Chinese punishments meted out to Madden included severe restrictions on the food he received, but what he did get he shared with other sick prisoners.

During this period he openly resisted all enemy efforts to force him to collaborate, to such a degree that his name and example were widely known through the various groups of prisoners.

Testimonials have been provided by officers and men from many units of the Commonwealth and Allied Forces which show that the heroism he displayed was quite outstanding.

Despite repeated beatings and many other forms of ill-treatment inflicted because of his defiance to his captors, Private Madden remained cheerful and optimistic.

Although deprived of food because of his behaviour, resulting in severe malnutrition, he was known to share his meagre supplies purchased from Koreans with other prisoners who were sick.

This gallant soldier's outstanding heroism was an inspiration to all his fellow prisoners.Madden's George Cross was presented to his sister, Mrs Florence Regan, at Government House, Sydney, on 9 May 1956 by the Governor of New South Wales, Lieutenant General Sir John Northcott.

[2][15] Madden's body was recovered following the Korean Armistice Agreement and was subsequently buried in the United Nations Memorial Cemetery at Busan, South Korea.