[1] The Liberals had held power for 22 years until their defeat in the 1957 federal election on June 10, 1957, which returned a Progressive Conservative minority government.

[2] Donald Hugh Mackay, Mayor of Calgary, withdrew his candidacy a week before the convention.

Former Finance Minister Walter Edward Harris, who had lost his seat in the election, had initially been expected to be Pearson's main competitor but did not run.

[3] Newfoundland MP and former Minister for Citizenship and Immigration Jack Pickersgill was also expected to run but did not stand.

[3] Pearson was the choice of the party establishment, had strong support from MPs in Quebec and Toronto, and won overwhelmingly on the first ballot and was also helped by being awarded the 1957 Nobel Peace Prize weeks before the convention.