In 2006, Dennis was elected as an Election Committee Member for the Legal Functional Constituency, and was re-elected in 2011. In 2007, he co-founded The Professional Commons, a public policy think-tank, and in 2008, he joined the Citizens Commission for Constitutional Development headed by the former Chief Secretary, Mrs. Anson Chan. He took part in the 2011 District Council Election but he was defeated. In 2012, he succeeded Margaret Ng and won the seat of Legal functional constituency in Legislative Council.
Political strategy
On assuming office as the legal-sector lawmaker, Kwok expressed support for the use of filibustering tactics by the pro-democracy camp, arguing that "the existing rules of procedure already make it sufficiently difficult for members to continue to filibuster without limitation". He said he would challenge any effort by the pro-government camp to inhibit the practice. From October 2019 to May 2020, while Kwok was Deputy Chairman of Legco's House Committee, no election for the vacant post of its Chairman took place, for which Kwok was accused by the Hong Kong and Macau Affairs Office and other pro-government voices of misconduct by paralysing Legco through filibustering tactics. In April 2020, pro-establishment lawmakers argued that Dennis Kwok was "no longer fit" to preside over sessions as his continued filibustering tactics had left multiple pieces of legislation in limbo. On 15 May 2020, Legco president Andrew Leung removed Kwok from the post of committee Deputy Chairman and imposed Finance Committee chair Chan Kin-por in his place. The move was vociferously opposed by democratic members, and led to shouting and scuffles in the chamber, during which eleven opposition lawmakers were ejected. The following week, Starry Lee was re-elected Chair, and the committee proceeded with addressing a backlog of bills for review.
Disqualification
Five weeks ahead of the 2020 Hong Kong Legislative Council Election, on 30 July, as Kwok prepared to defend his seat, the government stated that he was among a dozen pro-democracy candidates whose nominations were 'invalid', under an opaque process in which, nominally, civil servants - returning officers - assess whether, for instance, a candidate had objected to the enactment of the national security law, or was sincere in statements made disavowing separatism.
