This led the Hong Kong government to require future candidates a written declaration to confirm their political stance.

[6] In 1953, Leung's grandfather graduated from the university, and was allocated to work in Xinjiang Province Bureau of Mine for seven years, later resided in Zhuhai.

He then realised Hong Kong people protest to pursuit democracy and felt touched with their passion to preserve the truth of history.

[12] He studied at the University of Hong Kong, majoring in Philosophy with a minor in Politics and Public Administration,[8][9][13][14] and graduated with a Bachelor of Arts in 2016.

[15] He felt disappointed with the Hong Kong government ignoring the will of people, forcibly passing the Express Rail Grant and postponing the implementation of dual universal suffrage.

[8] In Summer 2014, People's Republic of China has passed the "831 decision" and White paper, this led him to believe that the HKSAR government had decided to ignore the promise made in Sino-British Joint Declaration.

[17] In September 2014, Umbrella Revolution erupted, besides part-timing in an art gallery and studying, Leung spent most of his time joining the movement.

[8] On 30 November, Leung and a group of protesters occupied the Central Government Complex, in response to the call from Hong Kong Federation of Students and Scholarism.

[8] After facing clearance from Hong Kong Police Special Tactical Squad, he believed occupational movements could not lead to changes.

[18] In 2015, Localist camp Hong Kong Indigenous was founded,[19] to support street hawkers near districts of Sham Shui Po and Mong Kok.

[18] In March 2015, under the referral from his classmate, Leung met Ray Wong, another political activist, but was unable to join Hong Kong Indigenous.

[21] In December 2015, Leung decided to participate 2016 New Territories East by-election, with the aim of promoting Localism ideology, testing his approval rate,[20] and encouraging young politicians.

[18] On 15 January 2016, Leung was nominated to represent Hong Kong Indigenous to run for New Territories East by-election,[19][22][23] and was endorsed by Youngspiration, another localist group.

[25] Leung organized a small election parade in Sheung Shui,[26] to explain the social problems brought by parallel importers, and was not interfered by the police.

[19][34][38][39][40] However, Leung received supports from other political organizations and activists such as Youngspiration, Civic Passion, LegCo councilor Wong Yuk-man, Chin Wan.

[47][48] At that time, Leung and Ray Wong were invited to join InterEthnic InterFaith Leadership Conference in Dharamshala, India, organized by 14th Dalai Lama.

[51][52] In July 2016, Electoral Affairs Commission released new election measures, directed against activists with Hong Kong Independence stance, requiring all candidates to sign declarations to confirm their support to Basic Law, and Hong Kong is an inseparable part of China as stated in the Basic Law.

[47][53][54] Leung applied to elect for New Territories East District,[55] and initially refused to sign the declaration and asked for judicial review.

[55][56][57] For this, Leung and Avery Ng sought judicial review with the High Court, claiming Electoral Affairs Commission has acted in excess of their authority, criticizing HKSAR Government's political censorship.

[14][55][59][60][61][62] In the end, six allegedly pro-independence nominees, including Leung[63] and Hong Kong National Party convener Chan Ho-tin, were disqualified by the committee,[14][64] the reason being the returning officer refused to believe their claims were genuine.

[6][21] In September, Leung and Ray Wong participated in Seventh International Conference of Tibet Support Groups, organized in Brussels, Belgium.

[96] Leung initially wanted to incorporate localism ideology into mainstream political agenda, and provide the rights for Hong Kong people to determine their future.

[101] In 2015, Leung and Ray Wong advocated protesters to use Black bloc strategy to protect each other,[102] yet he did not deny the actions of throwing rocks and arson, during Monk Kok civil unrest.

Tai Kung Pao once commented on Leung's clear mind, quick response, and excellent communication skills,[115] believing HKSAR Government need to treat the by-election results seriously.

However, no mainstream cinema in Hong Kong was willing to screen the film, renewing fears about self-censorship and suppress of freedom of speech.

"Liberate Hong Kong, revolution of our times" slogan was widely used and Lost in the fumes was a highly successful political documentary.

[122] On 27 May 2020, HKU uploaded several group photographs, dated on 18 February 2014 at Ricci Hall 85th Anniversary with other alumni to show condolences, but Leung's part was found to be intentionally scrapped.