He was formerly the leader of the Civic Party and a member of the Legislative Council of Hong Kong, representing New Territories East after winning the 2016 by-election.

[2] Yeung is currently chairman of the New Territories East branch of the party and member of the Appeal Panel (Housing),[3] and also co-host of the political talk-show "Teacup in a Storm" on D100 radio station.

From his leading position in opinion polls, he cooperated with Labour Party's Fernando Cheung and later on with other pan-democrat candidates to split the votes evenly to maximise the block's chances of winning seven out of the nine seats.

Five weeks ahead of the (subsequently postponed) 2020 Hong Kong Legislative Council Election, on 30 July 2020, as Yeung 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.

[6] On 6 January 2021, Yeung was among 53 members of the pro-democratic camp who were arrested under the national security law, specifically its provision regarding alleged subversion.

[8] On 28 February 2021, Yeung was among 47 members of the pro-democratic camp who were officially charged with conspiracy to commit subversion under the national security law.