Mardi Seng is a Senator in the Kingdom of Cambodia, President of the Khmer Will Party, and Chairperson of the Council of Asian Liberals and Democrats (CALD), the only regional alliance of liberal and democratic political parties in Asia.
Born in Cambodia in 1965, the eldest of five children of a schoolteacher and a tailor, he was ten years old when the Khmer Rouge seized Phnom Penh on 17 April 1975. His father was killed three days later. His family, branded “New People” for being city dwellers, was marched into the countryside, forced into agricultural labour, and later held for five months in a prison camp, where his mother was taken and killed in June 1978. Led by their grandmother, Mardi and his four siblings escaped to Thailand after the regime fell and, on 23 December 1980, arrived in Grand Rapids, Michigan, sponsored by Millbrook Christian Reformed Church.
He earned a Bachelor of Arts in Economics from Calvin College and an MBA from Northeastern University in Boston, where his co-op placement was as a bank examiner with the U.S. Office of the Comptroller of the Currency. He went on to work as an internal auditor at Fleet Financial Group — building, as he wrote at the time, the professional skills he intended to bring home to Cambodia.
After nearly three decades in the United States, he did exactly that. In Cambodia he served as Treasurer of the Sam Rainsy Party and led its national election campaigns across four election cycles; served in the Senate, where he was Secretary of the Anti-Corruption Commission; and became Treasurer of the Candlelight Party. When the Candlelight Party was barred from the 2023 national election, he stood in the February 2024 Senate election on the Khmer Will Party list and won one of the three opposition seats in the 62-member chamber.
As CALD Chairperson he has opened election observation missions in Taiwan, addressed the RenewPAC Summit of European and African leaders in Abidjan, and been received as guest of honour by the Parliamentary Caucus for Universal Values in the Indo-Pacific at Japan's National Diet. In 2026 he was the first guest of Forum 2000's “A Life in Democracy” series, launched at the Forum for Democratic Cooperation in Taipei.
His sister, Cambodian-American human rights lawyer Theary Seng, has been imprisoned in Cambodia since June 2022. He works, publicly and behind the scenes, for her release and for that of every Cambodian political prisoner.