YB Lee is also the Chairman of Centre for Regional Strategic Studies (CROSS) and President of Malaysia-China Technology Promotion Association.

He defeated defending MLA Pang Tsu Ming of Barisan Nasional (BN) and an independent candidate by a majority of 3,200 votes.

His master thesis, titled “GPS Taxi Dispatch System Based on A* Shortest Path Algorithm”, has been cited in several journal articles.

He co-authored books including "Jiwa Merdeka" and "Green Political Reform" (绿色政改), and is a contributor to The Edge, Malaysiakini and Oriental Daily.

[citation needed] Being active in international engagement and training, Lee was awarded the Most Outstanding Alumnus of Konrad Adenauer Stiftung Young Politicians (KASYP) program in 2019.

In March 2015, Lee participated in the "Kita Lawan" ("We Fight") movement, which organized street protests calling for reforms and the release of opposition leader Datuk Seri Anwar Ibrahim.

On September 8, 2015, he, along with other activists and opposition politicians, was charged under Section 4(2)(c) of the Peaceful Assembly Act 2012 for participating in a street protest that began in front of the Sogo Complex and ended at the fountain at the Jalan Tun Perak intersection on March 21, 2015.