Zhou excelled at school, and was eventually accepted to enroll at the prestigious Suzhou High School, one of the most prominent secondary schools in the Jiangnan region. Zhou had good grades and was involved in extra-curricular activities, including the school's political ideology group as well as the events promoting literacy. In 1961, after obtaining stellar results on his Gaokao exams, he was admitted to the Beijing Institute of Petroleum (now China University of Petroleum) soon after, and became the pride of his village. He majored in geophysical survey and exploration.

In November 1964 Zhou became a member of the Communist Party of China. In 1966, the Cultural Revolution ensnared Beijing's higher education institutions. Zhou was told by the authorities to "wait for an assignment" while the political struggles wreaked havoc on China's universities. He waited for a year. He joined geological survey work in north-east China in 1967, assigned to become an intern technician at factory No. 673 at the Daqing oil field. In 1970, Zhou was promoted to lead the geological survey division of a local department charged with carrying out an ambitious petroleum drilling initiative set out by the Party's top leadership.

At Liaohe, Zhou met Wang Shuhua (Chinese: 王淑华), a factory worker from Hebei province, whom he later married. As the Liaohe exploration team grew, Zhou eventually became responsible for over 2,300 employees in his department. His work consisted mainly of leading teams to unexplored, barren territory to conduct site surveys to assess the potential for Future oil drilling. He was known to be great at maintaining good interpersonal relationships with his superiors and subordinates, and gained significant personal clout. During some years, Zhou did not go back to his home in Jiangsu even during the Chinese New Year holiday period, which is a time traditionally reserved for family reunions. Instead, Zhou would visit his colleagues who were working in harsh winter conditions in remote areas. Beginning in the 1970s, Zhou would gain rapid career advancement. He owed much of his career growth to his mentors from the Beijing Institute of Petroleum, who were working in executive positions at the Liaohe oil fields at the time. In particular the university's President was known to be fond of Zhou's skills and was eager to promote him. In 1983, with the Director of the Liaohe Oil Field Management Bureau being transferred for a job in Beijing, Zhou was promoted to manage day-to-day affairs of the oil field. Moreover, given the oil field's prominence in the municipal affairs of the city of Panjin, Zhou became concurrently the Mayor of Panjin and the city's deputy party secretary. Zhou's stint as mayor was his first major role in government.

Zhou's son, Zhou Bin, born in 1972, was a prominent oil and gas executive who ostensibly used his father's connections to further his own Business interests. The younger Zhou was the primary shareholder and Chairman of Beijing Zhongxu Yangguang Energy Technology Holdings Ltd. Zhou Bin was investigated, tried, and sentenced to 18 years in prison. The younger Zhou is married to Chinese-American Huang Wan (黄婉), whom he met while studying oil and gas exploration in Texas. Huang's mother, Zhan Minli (詹敏利), held a stake in a number of companies with Business dealings with China National Petroleum and lives in southern California. Zhou's younger son, Zhou Han, maintains a comparatively lower profile, and was not close to his Father.

In 1973, Zhou Yongkang was promoted to head the Geophysical Exploration Department of the Liaohe Petroleum Exploration Bureau, located in Panjin, Liaoning. Liaohe would eventually become one of the China National Petroleum Corporation's (CNPC) largest oil fields. Zhou was seen as a hard-working and emotionally mature presence to his colleagues; he did not drink or smoke, and would rarely speak based on script. He would reputedly talk unscripted for hours on end while keeping his colleagues engaged.

In 1985, Zhou Yongkang left Liaoning for Beijing to become the Deputy Minister of Petroleum Industry. In 1988, the ministry later folded and became a state-owned enterprise, the predecessor of the China National Petroleum Corporation (CNPC), China's largest Energy company. Zhou became a member of the company's senior executive team and was named deputy general manager. In March 1989, as part of the government's overall strategy to move oil production from east to west, Zhou led an oil and gas exploration and survey team to begin work in the Tarim Basin in the Xinjiang region of far-west China, near the city of Korla.

Zhou's case was unprecedented, as no corruption investigation had ever been initiated against a member of the elite Politburo Standing Committee. The last PSC member to be ousted politically was Zhao Ziyang in the aftermath of Tiananmen in 1989, and the last PSC members to be put on trial were those of the Gang of Four following the Cultural Revolution.

In the mid-1990s, Zhou spearheaded CNPC's "go global" initiatives, winning bids for large projects in Sudan, Venezuela, and Kazakhstan. Zhou was particularly involved in the Sudan Nile petroleum project, including the construction of the Greater Nile Oil Pipeline, CNPC's first major project outside of China. Zhou travelled to the African country 14 times. Beginning in 1996, Zhou became general manager (chief executive) of the CNPC. As chief executive, Zhou was instrumental in the company's restructuring and the preparation the initial public offering of the company's subsidiary PetroChina. In October 1997, Zhou gained a seat on the Central Committee of the Communist Party, a leadership assembly of some 200 top political figures of the party.

Zhou rose through the ranks of the Communist Party through his involvement in the oil and gas industry, starting as a technician on the Daqing oil field during the Cultural Revolution. He was at the helm of the China National Petroleum Corporation between 1996 and 1998, then became Minister of Land and Natural Resources until 1999, and subsequently Party Secretary of Sichuan, then China's second most populous province. Zhou was a State Councilor of the State Council from 2003 to 2008 and also a member of the Party Secretariat of the Central Committee. He served as the Minister of Public Security from 2002–07, before being promoted to the PSC. Zhou retired at the 18th Party Congress in 2012.

In March 1998, Zhou was elevated to become Minister of Land and Resources in Premier Zhu Rongji's cabinet. The "mega-ministry" was created after a merger of the formerly separate Ministry of Geology and Mining, Administration of National Land, National Administration of Oceans, and the National Surveying and Mapping Bureau. As minister, Zhou, upon finding that his staff did not have adequate housing, initiated a housing construction program for the department's Engineers and senior technical staff.

In 1999, Zhou became Party Secretary of Sichuan, the province's top political office. Sichuan was China's second most populous province at the time. Prior to Zhou, most of Sichuan's provincial Leaders originated from the province. Zhou, an outsider, brought change to the province's political landscape. He spearheaded economic modernization policies and in particular focused on agricultural modernization. Sichuan was known to be a province highly dependent on agriculture, and its government operated at a slower pace compared to those of China's coastal regions. Zhou was known for his quick and efficient decision-making, significantly altering the traditionally lax culture of the province's civil Service.

During Zhou's tenure in Sichuan, the province's GDP grew at an average rate of 9.5% a year. One of his major achievements was securing investment from large multinationals such as Intel. The company opened a new computer chip factory near Chengdu shortly after Zhou left his post in Sichuan. He also focused on improving tourism resources, significantly revamping the Mount Emei scenic region to attract more visitors. Zhou also improved public safety in the province, for Example enacting policies that aimed to reduce accidents in the province's water lanes. On October 20, 2000, in the spirit of attracting investment for economic development, Zhou hosted visiting Chinese and international dignitaries and Business People at the China Western Forum held in Chengdu.

Zhou's political fate was subject to rife speculation in the lead-up to the 16th Party Congress held in the fall of 2002. Widely regarded as a rising political star, Zhou was said to be a leading candidate for Vice-Premier or entry into the top ranks of the Central Political and Legal Affairs Commission (Zhengfawei). The central government was also in need of a tough and uncompromising figure to take reins of China's security system in the post-9/11 global security paradigm. With his quasi-military style training in the oil sector and a reputation for being able to make tough decisions, Zhou got the nod to become Minister of Public Security in December 2002. He also earned a series of powerful posts in the party and government within the span of a few months, including membership in the Politburo, State Councilor, Deputy Zhengfawei Secretary, First Political Commissar of the People's Armed Police (China's paramilitary police force), and Secretary of the party's Central Secretariat (the party's internal policy execution and coordination body).

Zhou's time as the top official in Sichuan, the oil sector, and Public Security Minister earned him significant leadership experience and personal clout, as well as a complex network of patronage. In 2007, Zhou was transferred to fill the vacancy from Luo Gan, who retired from his leadership position as central Zhengfawei chief. With this powerful position, Zhou also gained a spot on the Politburo Standing Committee, the highest council of Communist Party rulers. With the expansion of Zhengfawei authority in the preceding years, Zhou became the top official responsible for China's courts, law enforcement, prosecution agencies, paramilitary forces, and domestic intelligence agencies. Even though he was ranked ninth in the party leadership hierarchy, Zhou, dubbed China's "security tsar" by select English-language media, emerged as one of the Standing Committee's most important members, and one of China's most powerful men.

In his position as national Zhengfawei chief, Zhou oversaw extensive security preparations for the 2008 Beijing Olympics, the 60th anniversary celebrations of the founding of the People's Republic of China in 2009, and Expo 2010 in Shanghai. At around this time, "weiwen" (维稳; roughly, "protecting stability") became a top political priority of the Chinese government. Zhou headed the national weiwen task force, overseeing law enforcement, suppression of dissent, state surveillance, and combating separatist movements in Xinjiang and Tibet. By 2011, during the unfolding of Arab Spring and the subsequent "Jasmine Revolution" movement, the national weiwen budget, valued at 624.4 billion yuan (US$95 billion), had exceeded the military budget for the first time in history.

Several leaked U.S. diplomatic cables from Wikileaks have alleged Zhou's involvement in Beijing's cyber attack against Google, though the claim's veracity has been questioned. Other cables said it was "well-known" that Zhou Yongkang controlled the state monopoly of the oil sector. Zhou also served as China's 'high representative' in matters relating to North Korea, attending the Arirang Festival as a guest of Kim Jong-il before Kim died in 2011.

The new party leadership under Xi reportedly began planning the crackdown on Zhou beginning in 2012. Xi's 'tough talk' on corruption began immediately after his ascension to the post of General Secretary. In his first days in office, Xi vowed to crack down on "tigers and flies", meaning extremely powerful officials as well as petty ones. Xi moved quickly to set a new standard for expected behavior of party officials, issuing a series of guidelines to clean up the party bureaucracy. Xi may have also been concerned that Zhou might use his influence and power to turn various state security entities into tools for advancing his interests, and in the process undermine the central authority of the state.

Zhou's son Zhou Bin absconded to the US in early 2013, and returned after negotiations with Chinese authorities. In June 2016, Zhou Bin was found guilty of taking 222 million yuan ($34m) in bribes and illegally trading in restricted commodities, and 350 million yuan ($53m) of illicit gains were confiscated; Zhou's wife, Jia Xiaoyue, was fined 1m yuan ($150,000) for bribe-taking. Zhou son and wife were sentenced to 18 years and 9 years imprisonment respectively.

On July 29, 2014, state media formally announced an internal party investigation against Zhou Yongkang's "violations of party discipline", but did not mention any Criminal wrongdoing. Several months later, the party investigation concluded that Zhou abused his power for the illicit gain of his family, friends, and associates, took "large amounts in bribes personally and through his family and associates; abused his power to further the interests of his family, mistresses, and associates; committed adultery with multiple women and engaged in the exchange of money and favours for sex; and leaked state and party secrets." State media announced Zhou's arrest to face Criminal proceedings on December 5, 2014. He was expelled from the Communist Party of China. Zhou was the first Politburo Standing Committee member to be expelled from the party since the fall of the Gang of Four in 1980 at the conclusion of the Cultural Revolution.

In the days leading up to the anticipated trial, Supreme Court President Zhou Qiang (no relation) told an assembled international press conference that Zhou Yongkang's trial would be "open and in accordance with the law." In April 2015, Zhou Yongkang was formally charged with abuse of power, bribery, and intentionally leaking state secrets, and scheduled to face trial at the Tianjin First Intermediate People's Court. Overseas Chinese media was rife with speculation about the 'treatment' Zhou was to receive. However, Zhou's trial unexpectedly took place behind closed doors. On June 11, state media made an announcement – without any apparent warning – that Zhou's verdict had already been reached. The official report on Zhou's trial was brief, and stated that he had been convicted on all three charges. The legal sentence, according to the state, was life in prison for bribery, seven years for abuse of power, and four years for "leaking state secrets." The court decided that Zhou could serve prison terms concurrently and amalgamated the sentences into one 'combined' life sentence. The total value of bribes taken by Zhou and his family was said to be 129.7 million yuan (~$18.87 million). State television showed Zhou pleading guilty with a head of fully gray hair, in contrast to his combed jet black hair dye he was known for prior to his retirement.

Owing to the far-reaching impact Zhou's case would have on the party as well as the potential for intra-party conflict, Xi also reportedly sought the blessing of former General Secretary Jiang Zemin and Hu Jintao as well as other 'party elders'. Jiang was said to have met with Xi several times in Beijing between June and July to discuss Zhou Yongkang. During these meetings, Xi was said to have directly elaborated to Jiang on Zhou's alleged crimes, as well as convincing Jiang of the potential harm to the party and the state if Zhou were not brought down. Jiang, though initially reluctant, eventually threw his weight behind Xi. Jiang subsequently applauded Xi's leadership skills during a visit by former U.S. Secretary of State Henry Kissinger. Hu Jintao was reportedly fully supportive of investigating Zhou prior to the power transition to Xi Jinping at the 18th Party Congress. Zhou himself reportedly sought two audiences with Xi, during which he discussed his contributions to the country and attempted to plead clemency, to no avail.