The early history of Kolasib is deeply intertwined with the migration of the Mizo tribes (formerly referred to as the Lushai by British administrators) who settled in the region between the 18th and 19th centuries. The area that is now Kolasib was traditionally ruled by local Mizo chieftains before the British annexation of the Lushai Hills in the late 19th century.
During the British colonial era, the northern part of Mizoram was strategically important as a buffer and transit route between the plains of Assam (Cachar) and the deeper mountainous territories of the Lushai Hills. Following India's independence, Kolasib remained part of the massive Aizawl district within the state of Assam, and later the Union Territory of Mizoram.
A significant and turbulent chapter in Kolasib's modern history occurred during the Mizo National Front (MNF) uprising in 1966. In response to the insurgency, the Government of India implemented a policy of "village grouping" (similar to strategic hamlets) to isolate insurgents from the local population. Kolasib served as a major grouping center, forcing populations from surrounding smaller villages to relocate to the town, which permanently altered its demographics and expanded its size.
Kolasib became the headquarters of its own distinct district in 1998, following the bifurcation of the larger Aizawl district. Since then, it has seen steady infrastructural and economic development, solidifying its role as Mizoram's northern commercial anchor.