The Chief Minister of Karnataka is the head of government of the Indian state of Karnataka. As per the Constitution of India, the governor of Karnataka is the state's de jure head, but de facto executive authority rests with the chief minister, a template applicable to all other Indian states. Following elections to the Karnataka Legislative Assembly, the governor usually invites the political party (or a coalition of political parties) with a majority of assembly seats to form the government in the state. The governor appoints the chief minister, whose council of ministers is collectively responsible to the assembly. Given that he/she has the confidence of the assembly, the chief minister's term is for five years, renewable, and is subject to no term limits. Usually, the chief minister also serves as leader of the house in the legislative assembly.
Historically, this office replaced that of the dewan of Mysore of the erstwhile Kingdom of Mysore with India's constitution into a republic. Since 1947, there have been a total of twenty-three chief ministers of Mysore (as the state was known before 1 November 1973) and Karnataka. A majority of them belonged to the Indian National Congress (INC) party, including the inaugural officeholder K. Chengalaraya Reddy. The current and the longest-serving chief minister is Siddaramaiah, who has held the office for over seven years. INC's Veerendra Patil had the largest gap between two terms (over eighteen years). B. D. Jatti, served as the country's fifth vice president, while H. D. Deve Gowda, went on to become the eleventh prime minister of India. B. S. Yediyurappa who was the first chief minister from the Bharatiya Janata Party (BJP), served as the chief minister of the state for four terms in 2007, 2008, 2018 and 2019, the only one to do so. S. R. Bommai served as the chief minister representing the Janata Parivar, whose son Basavaraj Bommai became chief minister representing the BJP in 2021 becoming the second father-son duo to serve office after Deve Gowda and HD Kumaraswamy. There have been six instances of president's rule in Karnataka, most recently from 2007 to 2008.
The princely state of Kingdom of Mysore, which existed during the British Raj, was organised into Mysore state after the Indian Independence in 1947.
Following the adoption of the Constitution of India, the executive of the Mysore State was led by a chief minister.
On 1 November 1956, as per the States Reorganisation Act, which organised states along the linguistic lines, Mysore State was expanded with the inclusion of the Kannada-speaking districts of Bombay, Hyderabad and Madras States, and the entirety of Coorg. On 1 November 1973, Mysore State was renamed as Karnataka via the Mysore State (Alteration of Name) Act.