The city of Belgaum was built in the 12th century AD by the Ratta dynasty who were based at nearby Saundatti. The fort of Belgaum was built in 1204 by a Ratta officer named Bichiraja. Belgaum served as the capital of that dynasty between 1210 and 1250, before the Rattas were defeated by the Yadava Dynasty of Devagiri. Belgaum then briefly came under the sway of the Yadavas of Devagiri. The Khiljis of Delhi invaded the region at the turn of the 1300s and succeeded in ruining both the indigenous powers of the region, the Yadava and the Hoysalas without providing a viable administration. This lacuna was supplied by the Vijayanagara Empire, which had become the established power of the area by 1336. A century later, the town had become a bustling trading hub for diamonds and wood, owing to its favourable geographic location in the kingdom.

In 1474, the Bahmani Sultanate, then ruling from Bidar, captured the fort of Belgaum. Shortly afterwards, in 1518, the Bahamani sultanate splintered into five small states, and Belgaum became part of the Adilshahi sultanate of Bijapur. The Adilshahis reinforced the fort of Belgaum; much of the existing structure dates from 1519. In 1686, the Mughal emperor Aurangzeb overthrew the Bijapur sultanate, and Belgaum passed nominally to the Mughals. However, the Mughal Empire went into decline after the death of Aurangzeb in 1707, and his principal detractors, the Maratha confederacy, took control of the area during the rule of the Peshwas. In 1776, the country was overrun by Hyder Ali of Mysore, but was retaken by the Peshwa with British assistance. In 1818, the British deposed the last Peshwa and annexed his kingdom, which included Belgaum.

Belgaum was chosen as the venue of the 39th session of Indian National Congress in December 1924 under the President ship of Mahatma Gandhiji. The city served as a major military installation for the British Raj, primarily due to its proximity to Goa, which was then a Portuguese territory. Once the British left India, the Indian Government continued and still continues to have Armed forces installations in Belgaum. In 1961, the Indian government, under the Prime Ministership of Nehru used forces from Belgaum to end Portuguese rule of Goa.

When India became independent in 1947, Belgaum and its district became part of Bombay State. In 1956, the Indian states were reorganised along linguistic lines by the States Reorganisation Act, and Belgaum District was transferred to Mysore State, which was renamed Karnataka in 1972.

In 2006, the Government of Karnataka announced that Belgaum would be made the state’s second capital and that the city would be a permanent venue for the annual 15-day session of the state legislature.