The incumbent Chief Executive, Donald Tsang, had been elected to serve the remainder of the five-year term which was left unserved, due to the midterm resignation of his predecessor, Tung Chee-hwa.

Leung Chun-ying ran a successful campaign against Chief Secretary for Administration, Henry Tang, who was seen as the favorite candidate by Beijing officials and business tycoons.

[6] Other minor candidates included Kan Kit-hung (簡傑鴻),[7] Yu Wing-yin (余永賢), consultant of the Hong Kong Applied Science and Technology Research Institute,[8][9][10] Wu Sai-chuen (胡世全), a former DAB member[11] and Roger Chan Yuet-tung (陳乙東).

[16] Frederick Fung, former chairman of the Association for Democracy and People's Livelihood (ADPL), also expressed his interest in running for the post, and officially announced his decision to participate in the election on 8 December 2011.

[18][19] After Henry Tang became embroiled in an unauthorised building works scandal in February 2012, the field of potential pro-Beijing candidates once again opened up: New People's Party legislator Regina Ip re-announced her interest in running for the post on 20 February; at the same time, Legislative Council president Jasper Tsang of the Democratic Alliance for the Betterment and Progress of Hong Kong (DAB) also said he was "seriously considering" running for the post.

[28]"Inevitably, [Tang's] refusal to quit has put Beijing in a difficult position as signs of unwavering support will be taken as evidence that the election has a pre-determined winner.

In early 2012, it emerged that support for Tang may have been played up by people close to Liao Hui, director of the Hong Kong and Macau Affairs Office from 1997 to 2000, to the detriment of Leung, who is an equally acceptable candidate to top leaders.

Top Chinese leaders have stipulated that the next CE would have to be patriotic in the eyes of both Beijing and Hong Kong, have governing and management skills, and command wide public acceptance.

[39][40] Li Jianguo, vice-chairman of the Standing Committee of the National People's Congress, informed local NPC deputies in January 2012 that Leung and Tang were both "acceptable" to Beijing as chief executive candidates, adding that he hoped to see a fair fight in the race.

[41] Speaking at a press conference after the close of the fifth plenary session of the 11th National People's Congress, premier Wen Jiabao reiterated the government's position.

[42]"I believe that as long as the principle of openness, justice and fairness is observed and relevant legal procedures are complied with, Hong Kong will elect a chief executive who enjoys the support of the vast majority of Hong Kong people"Wen Jiabao, 14 March 2012[42]Analysts said that the fight between the two candidates has upset the political consensus Beijing has sought to cultivate, and caused the leaders embarrassment.

Afterwards, public concern was raised about Henry Tang's accusations during the debate that Leung had proposed suppressing freedom of speech by shortening the licence renewal term for Commercial Radio in 2003; Tang also alleged that Leung had said in a "top-level meeting" that the government would have to deploy the anti-riot police and use tear gas to handle protests after the massive peaceful demonstration on 1 July 2003 opposing the legislation of Hong Kong Basic Law Article 23.

[47] Albert Ho used the platform to demand Tang and Leung to state their positions on universal suffrage, in particular the abolition of functional constituencies in the Legislative Council, and on vindication of the Tiananmen protests of 1989.

[51] Pan-democrat Emily Lau specifically said Leung Chun-ying and Henry Tang were inviting 10,000 people out to wine and dine on public expenses, and that this was unfair and irresponsible when neither appeared to want to run for chief executive.

On 19 January Henry Tang admitted his communications advisor Lucy Chan Wai-yee had made a call to the Baptist University prior to the announcement of the unfinished result,[55][56] but denied that he interfered with the poll.

[61] In an exclusive in early 2012, East Week magazine said Leung was one of 10 judges in the 2001 concept planning competition for the West Kowloon Cultural District despite his company acting as a consultant for one of the competitors.

I have already reported the case to the jury committee chairman and government bodies ... One quantity surveyor under a particular professional team asked our company about related comments and information on land prices in West Kowloon.

[62] As the row continued, the government generated further controversy[64] on 8 February when it issued two statements, one explaining the failure of candidate Leung to declare a possible conflict of interest in the West Kowloon Reclamation Concept Plan Competition, and other that cleared Henry Tang Ying-yen of any conflict of interest relating to his decision to lower wine duties when he was financial secretary.

[65] However, Asia Sentinel suggested the selective leak of such allegations by the government who then refused to make public all the documents relating to the issue as requested by Leung himself was a smear originating from the Tang camp.

The government said that had written to seek consent from both Leung Chun-ying and the contestant's architects TR Hamzah & Yeang to release information concerning their respective roles in the West Kowloon Reclamation Concept Plan.

"[87][88] The South China Morning Post cites a reliable source that Beijing was "surprised and disappointed" by Tang's violation of a basic principle, and that his chances were over from that moment.

[88] During the Hong Kong Chief Executive election, 2012, persistent rumours resurfaced of Leung's undeclared membership of the Chinese Communist Party (CCP).

[95] The Hong Kong Journalists Association, which noted that the HKEJ had received complaints about its coverage from central government's liaison office, and condemned the "open violation" of the one-country two-systems principle.

The IFJ cites an anonymous senior journalist for a Hong Kong newspaper saying that the Liaison Office had called several times "during the last two weeks" criticising the newspaper for alleging that the CLO had attempted to influence EC members; One publisher who is member of the EC also reportedly received calls from the Liaison Office with coded references to the preferred candidate: in line with the shift in reported preference from Tang to Leung, he said that initial emphasis was on 'experience' and 'temperament', but later switched to 'popularity'.

In the piece, he opined that "supporting either party would not be conducive to the situation", but the published version read: "If there is really a need to make a choice, then, let's choose Mr Leung Chun-ying."

As only IP numbers from abroad were allowed access, organisers believe it was "systematic hacking" from within Hong Kong, seeking to prevent people from voting.

[119] The SCMP cites other sources that the central government had mobilised to lobby undecided Election Committee members, or those who nominated Tang, to support Leung.

More than 40 EC members who had nominated Tang confirmed that they had been approached by the central government's liaison office in Hong Kong to switch their support to Leung.

Liaison Office deputy head Li Guikang (黎桂康) was reported to have met the representatives of the five leading business organisations for one and a half hours; they did not reveal the content of their discussions.

[137] When EC members arrived to cast their votes on the morning of 25 March, they were greeted by protesters outside the Hong Kong Convention and Exhibition Centre, the venue of the election.