Emperor Wu of Han's reign lasted 54 years – a record not broken until the reign of the Kangxi Emperor more than 1,800 years later and remains the record for ethnic Chinese emperors. His reign resulted in a vast expansion of geopolitical influence for the Chinese civilization, and the development of a strong centralized state via governmental policies, economical reorganization and promotion of a hybrid Legalist–Confucian doctrine. In the field of historical social and cultural studies, Emperor Wu is known for his religious innovations and patronage of the poetic and musical arts, including development of the Imperial Music Bureau into a prestigious entity. It was also during his reign that cultural contact with western Eurasia was greatly increased, directly and indirectly.

During his reign as Emperor, he led the Han dynasty through its greatest territorial expansion. At its height, the Empire's borders spanned from the Fergana Valley in the west, to northern Korea in the east, and to northern Vietnam in the south. Emperor Wu successfully repelled the nomadic Xiongnu from systematically raiding northern China, and dispatched his envoy Zhang Qian into the Western Regions in 139 BCE to seek an alliance with the Greater Yuezhi and Kangju, which resulted in further diplomatic missions to Central Asia. Although historical records do not describe him as being aware of Buddhism, emphasizing rather his interest in shamanism, the cultural exchanges that occurred as a consequence of these embassies suggest that he received Buddhist statues from Central Asia, as depicted in the murals found in the Mogao Caves.

Emperor Wu is considered one of the greatest emperors in Chinese history due to his strong leadership and effective governance, which made the Han dynasty one of the most powerful nations in the world. His policies and most trusted advisers were Legalist, favouring adherents of Shang Yang. However, despite establishing an autocratic and centralised state, Emperor Wu adopted the principles of Confucianism as the state philosophy and code of ethics for his empire and started a school to teach future administrators the Confucian classics.