Ma declared himself to be a Christian, and was affectionately known in Hong Kong as "Fat Ma" because of his portly physique.
Ma was previously Chief Financial Officer of PCCW, and before then a private banker with JP Morgan Private Bank, part of JP Morgan Chase. Ma gave up an annual salary of in excess of 10 million to join the government.
As a 'cabinet-level' political appointee under the Principal Officials Accountability System, he was a member of the Executive Council of Hong Kong. Ma entered the government in July 2002 as Secretary for Financial Services and the Treasury, and was appointed to Secretary for Commerce in July 2007.
In the early weeks of his government tenure, Ma he weathered the resignation calls for the "penny stocks fiasco" in July 2002, but has since earned recognition as one of the more astute and popular politicians, according to opinion polls. Ma has been praised by the for his even-handedness with all political parties. Ma's approval/disapproval rating stood at 55 percent/9 percent as at early July 2008.
As Secretary for Financial Services and the Treasury, one of Ma's jobs was to sell the the Tsang administration's proposals, which were abandoned for lack of support in December 2006.
On 24 June 2008, Ma resigned from the government for health reasons. He was diagnosed with "cavernous hemangioma" and "" in the brain.