First National Bank of Nokomis was founded and chartered on August 20, 1940. The bank operated in the east half of the lobby, until 1956 when space was doubled and the building was remodeled. The face was covered with green marble and gold colored metal, with an awning running the entire width of the building. In 1964, the west office wing and drive-up were added, and in 1984, the entire building was again remodeled. The face was redone in brick and stone and the awning removed. In 1998 the east office wing was added, along with the Board Room on the second floor.

In September 1987, First Nokomis Bancorp, Inc. (bank holding company) was formed and acquired all stock in the First National Bank of Nokomis. This expensive and complex step was taken to help ensure the bank can and will remain a locally controlled community bank.

In 1996, the First Nokomis Bancorp, Inc. purchased the Ayars State Bank of Moweaqua, Illinois (in the Moweaqua community since 1900). In 2000, the Ayars State Bank of Moweaqua was merged with the First National Bank of Nokomis and given the name Ayars Bank.

In 2006, First Nokomis Bancorp, Inc. purchased a branch from CIB in Arthur, Illinois and the branch was merged with the First National Bank of Nokomis and given the name First National Bank of Arthur.

In 2016, First Nokomis Bancorp, Inc. purchased a branch from Illini Bank in Stonington, Illinois and the branch was merged with the First National Bank of Nokomis and given the name Stonington National Bank.

There are approximately 43 full-time employees of the bank, many with over 10 years of service. The management of First National Bank of Nokomis is committed to goals which will increase capital and thus sustain the stability of the bank, allowing for growth and for additional services.