Skelton was a Professor of Politics and Economics at Queen's and the most powerful public servant of his day. He was born in Orangeville, Ontario and educated at Queen's, where he was a brilliant student in Classics and English (MA 1899).
He earned a PhD in Politics and Economics from the University of Chicago in 1908 and, a year later, returned to Queen's to succeed Professor Adam Shortt as Sir John A. Macdonald Professor of Political and Economic Science. He held this position until 1925 and served as Dean of Arts from 1919 until 1925.
Skelton was a popular teacher and wrote widely on economics, history, and current affairs. Throughout his career, he believed deeply that Canada must shed the vestiges of its colonial status and take control of its own affairs. He worked through the Liberal Party for this end.
He was close to Sir Wilfrid Laurier in the Prime Minister's last years and later wrote his biography. He was engaged by Prime Minister Mackenzie King as a part-time foreign policy consultant after the Liberals won the election of 1921. King took him on full-time in 1925 to serve as undersecretary of state for external affairs, an appointment he held until his death and in which he founded the modern Department of External Affairs.
He was offered Queen's principalship in 1930, but chose to stay in Ottawa - much to King's relief. An unassuming, unaffected, and hard-working man, he was the leading civil servant of his day. One of his colleagues in the civil service wrote that Skelton was the de facto "deputy Prime Minister of Canada."