Leslie Miscampbell Frost was a politician in Ontario, Canada, who served as the province's 16th premier from May 4, 1949, to November 8, 1961. Due to his lengthy tenure, he gained the nickname "Old Man Ontario"; he was also known as "the Silver Fox".

The premier of Ontario is the head of government of Ontario. Under the Westminster system, the premier governs with the confidence of a majority the elected Legislative Assembly; as such, the premier typically sits as a member of Provincial Parliament (MPP) and leads the largest party or a coalition of parties. As first minister, the premier selects ministers to form the Executive Council, and serves as its chair. Constitutionally, the Crown exercises executive power on the advice of the Executive Council, which is collectively responsible to the legislature.