Qi Jiguang was born in the town of Luqiao (鲁橋) in Shandong province to a family with a long military tradition. His forefather served as a military leader under Zhu Yuanzhang and died in battle. When Zhu Yuanzhang later became the founding emperor of the Ming Dynasty, he bestowed upon the Qi family the hereditary post of commander - in - chief of Dengzhou Garrison (登州衛), a district of the present day Penglai.

Qi Jiguang's father, Qi Jingtong (戚 景通), was an honest and upright man. He cultivated in his son a yearning for knowledge as well as a firm set of morals. When his father died, Qi Jiguang took over the command of Dengzhou Garrison at the age of seventeen. As his siblings were still young, he married Wang and left domestic affairs to her. Besides building up naval defense at the garrison, he also had to lead his troops to help in the defense of Jizhou (薊州), southwest of present day Beijing, against East Mongolian raiders during spring time from 1548 to 1552.

At twenty-two, Qi Jiguang headed for Beijing to take part in the martial arts section of the imperial examination. During this time, East Mongolian troops led by Altan Khan broke through the northern defense and laid siege on Beijing. Candidates participating in the martial arts exam were also mobilized to defend the capital. Qi Jiguang displayed extraordinary valor and military ingenuity during the battle, which eventually saw the defeat of the invaders.

In 1553, Qi Jiguang was promoted to Assistant Regional Military Commissioner (都指揮僉事) of Shandong's defense force against Japanese pirates. He disciplined his troops and reinforced the defense works well so that the pirates, seeing strong resistance in Shandong, had to move southwards to seek more vulnerable targets.

In the fall of 1555, Qi Jiguang was sent to Zhejiang, where the Japanese pirates colluded with their Chinese counterparts and expanded their forces. Together with two other renowned generals of his time, Yu Dayou and Tan Lun (譚綸), Qi Jiguang led the Ming soldiers to a decisive victory at Cengang (岑港) in 1558. Henceafter, his troops continued to deal fatal blows to the pirates at Taozhu (桃渚), Haimen Garrison (海門衛) and Taizhou.

With the situation in Zhejiang under control, Qi Jiguang began to concentrate on training a disciplined and effective army. He drafted mainly miners and farmers from the county of Yiwu because he believed these people to be honest and hardworking. He also oversaw the construction of 44 naval vessels of various sizes to be used against pirates at sea.

The first trial for Qi Jiguang's new army came in 1559. After a month long battle with Japanese pirates in the Taizhou Prefecture, with the pirates suffering over 5,000 casualties, Qi Jiguang's army established a name for itself among both the people of Zhejiang and its enemies.

Partly as a result of Qi Jiguang's military success in Zhejiang, pirate activities surged in the province of Fujian. More than 10,000 pirates had established strongholds along the coast from Fu'an (福安) in the north to Zhangzhou in the south. In July 1562, Qi Jiguang led 6,000 elite troops south into Fujian. Within two months, his army eradicated three major lairs of Japanese pirates at Hengyu (橫嶼), Niutian (牛田) and Lindun (林墩).

However, his own army also suffered significant losses to fighting and diseases. Seeing the pirate infestation in Fujian subdued, Qi Jiguang then returned to Zhejiang to regroup his force. The Japanese pirates took the opportunity to invade Fujian again, this time succeeding in conquering Xinghua (興化) (present day Putian). In April 1563, Qi Jiguang led 10,000 troops into Fujian and regained Xinghua. Over the next year, a series of victories by Qi Jiguang's army finally saw the pirate problem in Fujian fully resolved.

A final major battle against Japanese pirates was fought on the island of Nan'ao (南澳), which lies near the boundary between the provinces of Fujian and Guangdong, in September 1565. There Qi Jiguang joined arms with his old comrade Yu Dayou again to defeat the remnant of the combined Japanese and Chinese pirate force.

With the pirate situation along the coast under control, Qi Jiguang was called to Beijing in late 1567 to take charge of training troops for the imperial guards. In the next year, he was given command of the troops in Jizhou to defend against the Mongols. Qi Jiguang soon began the repair work on the segment of the Great Wall between Shanhai Pass and Juyong Pass (居 庸關). Meanwhile, he also directed the construction of watchtowers along the wall. After two years of hard work, more than 1,000 watchtowers were completed, giving the defensive capability in the north a great boost.

Qi Jiguang also conducted a month long military exercise involving more than 100,000 troops in winter 1572. From the experience of the maneuver he wrote Records of Military Training (練 兵實紀), which became an invaluable reference for military leaders after him. Over the sixteen years when Qi Jiguang was in Jizhou, not a single Mongolian raider crossed to the south of the Great Wall.

In early 1583, Qi Jiguang was relieved of his duty on the northern frontier and assigned an idle post in Guangdong. His already ill health worsened in the next two years, forcing him to retire to his hometown. He finally died in 1588, days before the Lunar New Year. His life was probably best summarized by his own poem:

For three hundred sixty days a year, I hold my weapon ready atop my steed.

Qi Jiguang was born during the reign of Jiajing Emperor, who was a devout follower of Taoism. The emperor devoted much of his time to seeking the way of immortality and, ironically, material indulgence. Most of the administrative matters, including military power, were left in the hands of the prime minister, Yan Song. Yan Song was an extremely corrupt official who abused his power. Every year, six tenths of the wages meant for troops guarding the frontlines would end up in his pocket. As a result, damaged defense works were not promptly repaired and acts of desertion were rampant.

When Qi Jiguang took over the command of Shandong's coastal defense, he had less than 10,000 troops at hand, though the recorded strength was 30,000. Furthermore, most of the deserters were young and strong men who could find a living elsewhere, leaving behind the old and the weak. The troops also lacked training and discipline, while the defense works were dilapidated due to years of negligence.

In addition, Yan Song also established a clan of court and district officials, which ostracized those who opposed its members. Besides covering up one another's acts of corruption, Yan Song's followers also blamed their inability on others, especially those whose capabilities threatened their positions. After the victory at Cengang (岑 港), not only was Qi Jiguang not credited for his valor, he was almost demoted over slander that he liaised with Japanese pirates.