Leong began his career in 1986 with the
GIC, Singapore's sovereign wealth fund, and subsequently worked with investment banks in Tokyo, London and Hong Kong, including at
Mitsubishi Bank,
Salomon Brothers and at
Merrill Lynch as a director. He returned to Singapore in 1997 to accept an appointment as Managing Director of
OCBC Securities. He stepped down from the position in 2005, He is currently the Chief Executive Officer of his own private equity firm, Timbre Capital. Leong was formerly the Deputy Chairman of the
Singapore Exchange Disciplinary Panel.
Political career Leong joined PSP in 2019 and served as its assistant secretary-general. In the
2020 Singaporean general election, Leong along with team members,
Tan Cheng Bock,
Hazel Poa, Nadarajah Loganathan and Jeffrey Khoo contested in the
West Coast GRC as part of a five-member PSP team but narrowly lost to the
People's Action Party with 48.31% of the vote. Notwithstanding, under the
Non-constituency Member of Parliament (NCMP) scheme, Leong was appointed an NCMP with effect from 16 July 2020. Four days later, he stepped down as assistant secretary-general of PSP to focus on his NCMP duties, with the position handed over to
Francis Yuen. In 2023, Yuen stepped down as secretary-general of PSP and Leong was elected secretary-general. On 23 February 2024, Leong stepped down as secretary-general of PSP after the Singapore government issued a
POFMA order which refuted the falsehoods made by Leong on his Facebook post. He remains on the party's governing body and as an NCMP. Leong was re-elected as secretary-general of the Progress Singapore Party on 26 March 2025. In August 2023, Leong filed a complaint against Balakrishnan, which Speaker of Parliament
Seah Kian Peng dismissed. In 2023, MP for
Bukit Batok SMC Murali Pillai claimed in Parliament that Leong had “advocated some form of rent control” during a debate on the Significant Investments Review Bill. Leong similarly filed a complaint to the Speaker of Parliament against this claim, which was also dismissed. In 2023, Parliament voted in favour of an amended motion Leong proposed on the impartiality of duties of the Speaker of Parliament. The same year, Leong's motion on housing policy was supported by all 11 opposition Members of Parliament, but failed to win the majority PAP's vote. Eugene Tan, an associate professor at
Singapore Management University, has described Leong as having a "dogged but confrontational style" in Parliament with a "folksy persona" that attempts to embody a "defiant underdog speaking for the masses". Felix Tan, a lecturer at
Nanyang Technological University, notes that "A vocal articulation of [Leong's] thoughts in parliament has given him... perhaps an increasing number of supporters for the way that he goes about voicing concerns amongst certain groups of Singaporeans." == Political positions ==