Born in Tokyo's Aoyama Palace (during the reign of his grandfather, Emperor Meiji) on 29 April 1901, Hirohito was the first son of 21-year-old Crown Prince Yoshihito (the future Emperor Taishō) and 17-year-old Crown Princess Sadako (the future Empress Teimei). He was the grandson of Emperor Meiji and Yanagihara Naruko. His childhood title was Prince Michi.

On the 70th day after his birth, Hirohito was removed from the court and placed in the care of the family of Count Kawamura Sumiyoshi, a former vice-admiral, who was to rear him as if he were his own grandchild. At the age of 3, Hirohito and his brother Yasuhito were returned to court when Kawamura died – first to the imperial mansion in Numazu, Shizuoka, then back to the Aoyama Palace.

When his grandfather, Emperor Meiji, died on 30 July 1912, Hirohito's father, Yoshihito, assumed the throne, and Hirohito became the heir apparent. At the same time, he was formally commissioned in both the army and navy as a second lieutenant and ensign, respectively, and was also decorated with the Grand Cordon of the Order of the Chrysanthemum.

Hirohito was formally proclaimed Crown Prince and heir apparent on 2 November 1916; but an investiture ceremony was not strictly necessary to confirm this status as heir to the throne.

In 1920 Hirohito was promoted to the rank of Major in the army and Lieutenant Commander in the navy.

Hirohito became Regent of Japan (Sesshō) on 29 November 1921, in place of his ailing father who was affected by a mental illness.

In 1923 he was promoted to the rank of Lieutenant-Colonel in the army and Commander in the navy.

On 27 December 1923, Daisuke Namba attempted to assassinate Hirohito in the Toranomon Incident but his attempt failed. During interrogation, he claimed to be a communist and was executed, but some have suggested that he was in contact with the Nagacho faction in the Army.

Prince Hirohito married his distant cousin Princess Nagako Kuni (the future Empress Kōjun), the eldest daughter of Prince Kuniyoshi Kuni, on 26 January 1924. They had two sons and five daughters.

In 1925 he was promoted to army Colonel and Navy Captain.

On 25 December 1926, Hirohito assumed the throne upon the death of his father, Yoshihito. The Crown Prince was said to have received the succession (senso).

In November 1928, the Emperor's ascension was confirmed in ceremonies (sokui) which are conventionally identified as "enthronement" and "coronation" (Shōwa no tairei-shiki); but this formal event would have been more accurately described as a public confirmation that his Imperial Majesty possesses the Japanese Imperial Regalia, also called the Three Sacred Treasures, which have been handed down through the centuries.

Starting from the Mukden Incident in 1931, Japan occupied Chinese territories and established puppet governments. Such "aggression was recommended to Hirohito" by his chiefs of staff and prime minister Fumimaro Konoe, and Hirohito never personally objected to any invasion of China.

According to Akira Fujiwara, Hirohito endorsed the policy of qualifying the invasion of China as an "incident" instead of a "war"; therefore, he did not issue any notice to observe international law in this conflict (unlike what his predecessors did in previous conflicts officially recognized by Japan as wars), and the Deputy Minister of the Japanese Army instructed the Chief of staff of Japanese China Garrison Army on August 5 not to use the term "prisoners of war" for Chinese captives. This instruction led to the removal of the constraints of international law on the treatment of Chinese prisoners. The works of Yoshiaki Yoshimi and Seiya Matsuno show that the Emperor also authorized, by specific orders (rinsanmei), the use of chemical weapons against the Chinese.

Hirohito narrowly escaped assassination by a hand grenade thrown by a Korean independence activist, Lee Bong-chang, in Tokyo on 9 January 1932, in the Sakuradamon Incident.

The assassination of moderate Prime Minister was followed by an attempted military coup in February 1936, the February 26 incident, mounted by junior Army officers of the Kōdōha faction who had the sympathy of many high-ranking officers including Prince Chichibu (Yasuhito), one of the Emperor's brothers. This revolt was occasioned by a loss of political support by the militarist faction in Diet elections. The coup resulted in the murders of a number of high government and Army officials.

When Chief Aide-de-camp Shigeru Honjō informed him of the revolt, the Emperor immediately ordered that it be put down and referred to the officers as "rebels" (bōto). Shortly thereafter, he ordered Army Minister Yoshiyuki Kawashima to suppress the rebellion within the hour, and he asked reports from Honjō every 30 minutes. The next day, when told by Honjō that little progress was being made by the high command in quashing the rebels, the Emperor told him "I Myself, will lead the Konoe Division and subdue them." The rebellion was suppressed following his orders on 29 February.

During the invasion of Wuhan, from August to October 1938, the Emperor authorized the use of toxic gas on 375 separate occasions, despite the resolution adopted by the League of Nations on May 14 condemning Japanese use of toxic gas.

On September 27, 1940, ostensibly under Hirohito's leadership, Japan was a contracting partner of the Tripartite Pact with Germany and Italy forming the Axis Powers.

On September 4, 1941, the Japanese Cabinet met to consider war plans prepared by Imperial General Headquarters.

On September 5, Prime Minister Konoe informally submitted a draft of the decision to the Emperor, just one day in advance of the Imperial Conference at which it would be formally implemented.

As war preparations continued, Prime Minister Fumimaro Konoe found himself more and more isolated and gave his resignation on October 16.

On November 2 Tōjō, Sugiyama, and Nagano reported to the Emperor that the review of eleven points had been in vain. Emperor Hirohito gave his consent to the war and then asked: "Are you going to provide justification for the war?" The decision for war against the United States was presented for approval to Hirohito by General Tōjō, Naval Minister Admiral Shigetarō Shimada, and Japanese Foreign Minister Shigenori Tōgō.

On November 3, Nagano explained in detail the plan of the attack on Pearl Harbor to the Emperor.

On November 5 Emperor Hirohito approved in imperial conference the operations plan for a war against the Occident and had many meetings with the military and Tōjō until the end of the month.

On November 26, 1941, US Secretary of State Cordell Hull presented the Japanese ambassador with the Hull note, which as one of its conditions demanded the complete withdrawal of all Japanese troops from French Indochina and China. Japanese Prime Minister Tojo Hideki said to his cabinet, "This is an ultimatum".

On December 1 an Imperial Conference sanctioned the "War against the United States, United Kingdom and the Kingdom of the Netherlands."

On December 8 (December 7 in Hawaii), 1941, in simultaneous attacks, Japanese forces struck at the Hong Kong Garrison, the US Fleet in Pearl Harbor and in the Philippines, and began the invasion of Malaya.

The Emperor made major interventions in some military operations. For example, he pressed Sugiyama four times, on January 13 and 21 and February 9 and 26, to increase troop strength and launch an attack on Bataan.

In the first six months of war, all the major engagements had been victories. Japanese advances were stopped in the summer of 1942 with the battle of Midway and the landing of the American forces on Guadalcanal and Tulagi in August.

The American Force Landed on Guadalcanal and Tulagi in August.

The Emperor recognized the potential danger and pushed the navy and the army for greater efforts. In September 1942, Emperor Hirohito signed an Imperial Rescript condemning to death American fliers Lieutenants Dean E. Hallmark and William G. Farrow and Corporal Harold A. Spatz and commuting to life sentences Lieutenants Robert J. Meder, Chase Nielsen, Robert L. Hite and George Barr and Corporal Jacob DeShazer. All had participated in the Doolittle Raid and had been captured.

On September 11 the Emperor ordered Sugiyama to work with the Navy to implement better military preparation and give adequate supply to soldiers fighting in Rabaul.

Throughout the following years from 1943 to 1945, the sequence of drawn and then decisively lost naval and land engagements was reported to the public as a series of great victories. Only gradually did it become apparent to the Japanese people that the situation was very grim due to growing shortages of food, medicine, and fuel as U.S submarines began wiping out Japanese shipping. Starting in mid 1944, U.S. air raids on the cities of Japan made a mockery of the unending tales of victory.

In early 1945, in the wake of the losses in Battle of Leyte, Emperor Hirohito began a series of individual meetings with senior government officials to consider the progress of the war. All but ex-Prime Minister Fumimaro Konoe advised continuing the war. Konoe feared a communist revolution even more than defeat in war and urged a negotiated surrender.

By mid-June 1945 the cabinet had agreed to approach the Soviet Union to act as a mediator for a negotiated surrender but not before Japan's bargaining position had been improved by repulse of the anticipated Allied invasion of mainland Japan.

In February 1945 during the first private audience with the Emperor which he had been allowed in three years, Konoe advised Hirohito to begin negotiations to end the war.

With each passing week victory became less likely. In April the Soviet Union issued notice that it would not renew its neutrality agreement. Japan's ally Germany surrendered in early May 1945.

In June the cabinet reassessed the war strategy, only to decide more firmly than ever on a fight to the last man. This strategy was officially affirmed at a brief Imperial Council meeting, at which, as was normal, the Emperor did not speak.

On July 26, 1945, the Allies issued the Potsdam Declaration demanding unconditional surrender. The Japanese government council, the Big Six, considered that option and recommended to the Emperor that it be accepted only if one to four conditions were agreed upon, including a guarantee of the Emperor's continued position in Japanese society. The Emperor decided not to surrender.

Everything changed after the atomic bombings of Hiroshima and Nagasaki and the Soviet declaration of war. And on August 10, the cabinet drafted an "Imperial Rescript ending the War" following the Emperor's indications that the declaration did not compromise any demand which prejudiced the prerogatives of His Majesty as a Sovereign Ruler.

On August 12, 1945, the Emperor informed the imperial family of his decision to surrender. One of his uncles, Prince Yasuhiko Asaka, asked whether the war would be continued if the kokutai (national polity) could not be preserved. The Emperor simply replied "Of course."

On August 14 the Suzuki government notified the Allies that it had accepted the Potsdam Declaration.

A faction of the army opposed to the surrender attempted a coup d'état on the evening of 14 August, prior to the broadcast. They seized the Imperial Palace (the Kyūjō incident), but the physical recording of the emperor's speech was hidden and preserved overnight. The coup was crushed by the next morning, and the speech was broadcast.

On August 15 a recording of the Emperor's surrender speech ("Gyokuon-hōsō", literally "Jewel Voice Broadcast") was broadcast over the radio (the first time the Emperor was heard on the radio by the Japanese people) announcing Japan's acceptance of the Potsdam Declaration. During the historic broadcast, the Emperor stated: "Moreover, the enemy has begun to employ a new and most cruel bomb, the power of which to do damage is, indeed, incalculable, taking the toll of many innocent lives. Should we continue to fight, not only would it result in an ultimate collapse and obliteration of the Japanese nation, but also it would lead to the total extinction of human civilization.

On September 22, 1987, the Emperor underwent surgery on his pancreas after having digestive problems for several months. The doctors discovered that he had duodenal cancer.

The Emperor appeared to be making a full recovery for several months after the surgery. About a year later, however, on September 19, 1988, he collapsed in his palace, and his health worsened over the next several months as he suffered from continuous internal bleeding.

On January 7, 1989, at 7:55 AM, the grand steward of Japan's Imperial Household Agency, Shoichi Fujimori, officially announced the death of Emperor Hirohito at 6:33 AM and revealed details about his cancer for the first time.

From January 7 until January 31, the Emperor's formal appellation was "Departed Emperor." His definitive posthumous name, Shōwa Tennō, was determined on January 13 and formally released on January 31 by Toshiki Kaifu, the prime minister.

On February 24, Emperor Hirohito's state funeral was held, and unlike that of his predecessor, it was formal but not conducted in a strictly Shinto manner. A large number of world leaders attended the funeral. Emperor Hirohito is buried in the Musashi Imperial Graveyard in Hachiōji, alongside Emperor Taishō, his father.