It flows from the northwestern slopes of the Alpine National Park in the Australian Alps, through the King Valley, and joining with the Ovens River at the rural city of Wangaratta.

[3] The King River rises below Mount Buggery, within Mansfield Shire, at an elevation exceeding 1,460 metres (4,790 ft) above sea level.

[3] The river is impounded by the William Hovell Dam to form Lake William Hovell, that provides water for approximately 24 square kilometres (9.3 sq mi) for irrigated crops, vineyards and grazing properties along the King River from Cheshunt to Wangaratta.

[4][5] A small 1.6-megawatt (2,100 hp) hydro-electric generator is driven by the river's outflow from the dam, with an average annual output of 3.7 gigawatt-hours (13 TJ).

[5][6] The river was given its English name by Hamilton Hume and William Hovell, explorers of the region, in honour of Captain Philip Gidley King, the third Governor of New South Wales, in office from 1800 to 1806.