Acknowledging the maharaja's noble and efficient kingship, John Sankey declared in 1930 at the first Round Table Conference in London, "Mysore is the best administered state in the world".

[7] At the time of his death, Krishnaraja Wadiyar IV was one of the world's wealthiest men, with a personal fortune estimated in 1940 to be worth US$400 million, equivalent to $7 billion in 2018 prices.

After the sudden death of his father in Calcutta in 1894, the widowed queen mother Kempananjammanni Devi ruled the state as regent from 1895 to 1902, until Krishnaraja Wadiyar reached the age of majority on 8 August 1902.

The study of the principles of jurisprudence and methods of revenue administration was supplemented by extensive tours of the state during which he gained immense knowledge of the nature of the country which he was later to govern.Shortly after the death of his father Maharaja Chamarajendra Wadiyar X on 28 December 1894, Krishnaraja Wodeyar IV, still a boy of eleven, ascended the throne on 1 February 1895.

[10] The yuvaraja was invested as the Maharaja of Mysore, with full ruling powers, by George Curzon, the Governor-General of India, on 8 August 1902 at a ceremony at Jaganmohana Palace.

Mysore became the first Indian state to generate hydroelectric power in Asia, and Bangalore was the first Asian city to have street lights, first lit on 5 August 1905.

The maharaja worked towards alleviating poverty and improving rural reconstruction, public health, industry and economic regeneration, education and the fine arts.

The Indian Institute of Science at Bangalore, which was initiated during his mother's tenure as regent, functionally started during his reign in 1911 with a gift of 371 acres (1.5 km2) of land and a donation of funds.