In the 1930s, Foshan stands as a vibrant center for Southern Chinese martial arts, bustling with various schools that compete and vie for talented disciples. Among these martial arts masters, Ip Man (Donnie Yen), the esteemed Wing Chun expert, remains remarkably humble. Although he possesses unparalleled skills, he leads a serene life, preferring to avoid public attention, dedicating his time to family, friends, and training. Unfortunately, his dedication to martial arts creates tension at home, as his wife often feels neglected due to his frequent training sessions and discussions about martial arts.
Despite not actively training others, Ip Man earns respect in Foshan through friendly and informal competitions with other local masters. His reputation skyrockets after he faces off against Jin Shanzhao, a brash and skilled Northern Chinese martial artist, and triumphs, which enkindles local pride among his fellow Southern stylists.
The peace of Foshan is shattered amid the Japanese invasion in 1937, turning the town upside down. With the Japanese commandeering his home as their headquarters, Ip and his family plunge into poverty, forced to move into a run-down dwelling. To provide for his loved ones, he reluctantly takes on a grueling job at a coal mine. General Miura (Hiroyuki Ikeuchi), a Karate expert, organizes vicious competitions where Chinese martial artists pit their skills against his military cadets, offering a meager reward of rice for each victory. Initially, Ip hesitates to join these brutal matches. However, upon discovering the disappearance of his friend Lin, he resolves to participate to uncover the truth.
Tragically, Ip arrives only to witness Lin's execution at the hands of Lieutenant Sato for taking rice after a previous contest. Infuriated by the loss of his friend, Ip challenges ten Karateka simultaneously. Despite having abstained from practicing Wing Chun to conserve scarce rations, he unleashes a ferocious display of martial prowess, demolishing the attackers and catching the attention of General Miura, who desires to observe more of Ip's skills.
As time passes, Miura's impatience grows due to Ip’s absence from the arena, prompting him to dispatch Sato and soldiers to find him. In a confrontational moment, Sato threatens Ip's wife, provoking Ip to defeat the soldiers with ease. Later, he seeks the help of his friend Chow Ching-Chuen (Simon Yam), who is plagued by extortion from a bandit group led by Jin Shanzhao. Ip offers to train Chow’s factory workers in self-defense using Wing Chun techniques. When the gang attempts to shake down the cotton mill again, the workers valiantly counterattack with their newfound skills, and Ip arrives to handle the situation, decisively taking down Jin Shanzhao and warning him to stay away.
Eventually, the Japanese forces discover Ip at the cotton mill. General Miura proposes that Ip teach martial arts to the soldiers in exchange for his life, but Ip staunchly refuses and challenges Miura for a public match, which the general accepts, knowing that declining would be dishonorable. The confrontation draws a crowd in the town square of Foshan. At first, the duel appears evenly matched, but soon, Ip's unmatched technique overwhelms Miura, who finds himself outmatched and suffers a devastating defeat.
With the general incapacitated and lying on the ground, victory is bittersweet for Ip as he glimpses his family amidst the adoring crowd. However, the triumph leads to chaos when Sato retaliates by firing at Ip, igniting a tumultuous fight between the Chinese spectators and the Japanese soldiers, culminating in a climactic moment when Li Zhao avenges a fallen comrade by killing Sato.
Amid the tumult, Ip is forcibly escorted away, yet the story does not end there. The epilogue unveils that he successfully escapes to Hong Kong, aided by his friend Chow Ching-Chuen, where he establishes a Wing Chun school, eventually becoming a mentor to future martial arts legends, including Bruce Lee.
