The history of Kayamkulam is closely associated with the ancient kingdom of Odanad, also known as Onattukara.

During the medieval period, Odanad emerged as an important regional kingdom. Kayamkulam subsequently developed as one of its major political and commercial centres. The presence of Kayamkulam Kayal and the surrounding waterways contributed significantly to trade, transportation and economic activities in the region.

During the 18th century, Kayamkulam became part of the Travancore Kingdom under Maharaja Marthanda Varma. Following the annexation of Kayamkulam, administrative arrangements in the region were reorganised under the leadership of Ramayyan Dalawa.

Krishnapuram Palace is one of the most important historical landmarks associated with this period. The palace represents the traditional architectural heritage of Kerala and the royal history of Kayamkulam.

According to records of the Kerala Department of Archaeology, the original form of the palace was constructed during 1750–1753 under the leadership of Ramayyan Dalawa and was later expanded and renovated during 1761–1764.

The famous Gajendra Moksham mural at Krishnapuram Palace is one of the notable examples of Kerala's traditional mural art.

According to the Census of India records, Kayamkulam was recorded as a Town in 1901 and attained Municipality status from 1921.

Over the years, Kayamkulam developed as an important centre for trade, education, healthcare, transportation and various service activities. The development of road and railway networks further strengthened its regional importance.

Today, Kayamkulam Municipality provides a wide range of civic services and undertakes various development and welfare activities for the people and the sustainable development of the urban area.