Clark was a Professor of Politics and Economics at Queen's and one of the most influential Canadian public servants of this century.
He was born in Glengarry County in eastern Ontario and educated at Queen's, where he was an extraordinary student.
In 1910, he earned a first class honours BA in Latin and French. He then enrolled in English, History, and Politics, and by 1912 took honours in those subjects as well - in effect, earning a total of five undergraduate degrees.
After graduate studies at Harvard University, Clark returned to Queen's in 1915 to teach Politics and Economics. In 1921, he turned to a career in business and spent most of the next decade with a real estate firm in Chicago.
The onset of the Depression in 1929 left him deep in debt and he returned to teaching duties at Queen's. His old professor, Oscar Douglas Skelton, by then a public servant, recruited him to Ottawa in 1932 and convinced Prime Minister R.B. Bennett (later a rector of Queen's) to appoint him Deputy Minister of Finance.
Clark greatly expanded the Department of Finance, was largely responsible for the creation of the Bank of Canada in 1935, and helped to lay the basis for the modern welfare state after the Second World War. He remained Deputy Minister until his death in 1952.