In 1888 a fruit farmer/nursery stock dealer, T.H. Leslie moved with his very large family to the prairie-land of southwest Arkansas where Gillett later came to be located. A street in present day Gillett is named after him, Leslie Avenue. He convinced other farmers to move to Arkansas as well, among them, several German immigrants. Stores were opened during 1888 and a post office was established. The residents of the town wanted the post office to be named Leslie but there was already a post office with that name in northern Arkansas. Instead the post office and the eventually the town came to be named Gillett after Francis Gillett of New York City, a underwriter for the railroad who visited the town in 1892.
Gillett's first school was called Prairie Cottage was used on Sundays as a sanctuary. In 1895 a new school building was erected and this one was made out of brick. The same year the town got a railroad station.
The town was incorporated in 1906 an Henry G. Leslie became its first mayor.
T.H. Leslie moved to Stuttgart in the middle of the 1890's but returned to the town that he helped found in the early 1900's. He passed away in 1903 and never lived to see the incorporation of the Gillett.