Dean attended the University of California at Berkeley before graduating with a commission in the US Army through the Reserve Officer's Training Corps (ROTC) in 1921.

[5] Following these appointments, Dean attended the US Army Command and General Staff College at Fort Leavenworth, Kansas before being assigned to a post on Oahu, Hawaii for two years.

[1] He held this office only briefly, before being assigned as assistant commander of the US 44th Infantry Division, under Major Generals James I. Muir and Robert L. Spragins beginning in late 1943.

[7] The division was to sail for the European Theater and Dean went with them despite being injured shortly before departure in a flamethrower accident which claimed the lives of two other soldiers.

[6] It trained for a month before entering combat on October 18, 1944, when it relieved the US 79th Infantry Division in the vicinity of Foret de Parroy, east of Luneville, to take part in the Seventh United States Army drive to secure several passes in the Vosges Mountains.

After regrouping, the 44th Infantry Division returned to the attack, taking Ratzwiller and entering the Ensemble de Bitche along the Maginot Line.

Fort Simserhof was captured by the Germans on December 19 and the 44th Infantry Division was forced to retreat to defensive positions east of Sarreguemines.

[9] After a short period of occupation duty, the 44th Infantry Division returned to the United States in July 1945 where it began training for deployment to the Pacific Theater.

The 44th Infantry Division was disbanded by the end of that month, and Dean was assigned to Fort Leavenworth again to organize and direct command classes.

Headquartered in Seoul, Dean maintained political control of the country until August 15, 1948, when the new South Korean government was elected and the occupation ended.

[12][13] He was moved to Yokohama in May 1949 to serve as chief of staff to the Eighth United States Army under Lieutenant General Walton Walker.

[15] Dean subsequently ordered a purge of suspected sympathizers of the Workers' Party of South Korea from the Korean Constabulary culminating in the summary execution of three sergeants.

The First Republic of Korea under President Syngman Rhee escalated the suppression of the uprising from August 1948, declaring martial law in November and beginning an "eradication campaign" against rebel forces in the rural areas of Jeju in March 1949, defeating them within two months.

[22] With the defeat of Task Force Smith, Dean ordered the US 34th Infantry Regiment and other elements of the division to conduct delaying actions south of Osan, but he was disappointed and frustrated by the result.

[32] Former regimental commander Lovless moved north to join L Company, along with newly arrived Colonel Robert R. Martin, a friend of Dean's.

[36][37] On July 12, Dean ordered the division's three regiments—the US 19th, 21st and 34th Infantry Regiments—to cross the Kum River, destroying all bridges behind them, and to establish defensive positions around Daejon.

[52] Without radios, and unable to communicate with the remaining elements of the division, Dean joined the men on the front lines, hunting the T-34 tanks with the help of the new shaped-charge, armor-piercing 3.5 inch "Super Bazookas", which had only been put into production two weeks before the war.

However, as they attempted to escape further they ran into another North Korean roadblock and were forced to continue on foot, crossing the Taejon River and climbing a nearby mountain.

[60] By July 22, with Dean still missing, the Eighth Army appointed Church commander of the 24th Infantry Division and promoted him to major general.

[61] Dean was widely believed to have been killed until October 1950, when US forces captured a North Korean soldier named Lee Kyu-hyun (이규현) near Pyongyang.

They began daily interrogations primarily aimed at forcing military intelligence from him or making him sign a written condemnation of the UN intervention in Korea, but Dean adamantly refused to do so.

Senior North Korean military leaders continued such interrogations through October 1950 but eventually gave up when Dean would not cooperate and was not intimidated by their threats.

[66] Dean later said he had tried to commit suicide because he feared he would break under torture and divulge critical intelligence to the North Koreans, such as the plans for Operation Chromite, of which he had been aware.

[67] Dean had no contact with the outside world until he was interviewed on 21 December 1951, by an Australian journalist, Wilfred Burchett, who was a war correspondent for Ce soir,[68] a French Left-wing newspaper.

When Dean returned to the United States, he received a hero's welcome and was presented with a number of decorations, including the Medal of Honor, which he was unaware he had been awarded.

[72] Three months after his return from Korea, Dean was assigned as the Deputy Commanding General of the Sixth United States Army at the Presidio of San Francisco in California.

[75][76] Dean maintained an athletic lifestyle for much of his life, picking up weightlifting and running when he was young, coaching basketball and, in his later years, he played tennis.

These actions indicate that Maj. Gen. Dean felt it necessary to sustain the courage and resolution of his troops by examples of excessive gallantry committed always at the threatened portions of his frontlines.

The success of this phase of the campaign is in large measure due to Maj. Gen. Dean's heroic leadership, courageous and loyal devotion to his men, and his complete disregard for personal safety.

[1] When the city of Daejeon built a Battle of Taejon memorial in 1981 they decided to include a statue that depicted Dean when he was firing his bazooka at North Korean tanks.