Mitchell Frederick Hepburn was the 11th premier of Ontario, from 1934 to 1942. He was the youngest premier in Ontario history, becoming premier at age 37. He was the only Ontario Liberal Party leader in the 20th century to lead his party to two majorities.

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.