The zoo had its origins in the Child Development Laboratory, which was started in 1937 and was operated by the Hogg Foundation and the American Association of University Women of Tyler.

The city granted an additional 40 acres (16 ha) to the zoo in 1976, and a large, long-term expansion project was undertaken.

Two white tigers, Meka and Willieking, were traded from the Alexandria Zoo in Louisiana in 2007 and have now been declared permanent displays, though they were originally only supposed to stay until the beginning of September 2007.

Animals born at the zoo include reticulated giraffes, flamingoes, black rhinoceros, jaguars, giant anteaters, and many others.

[6] Currently, a major remodeling is undergoing in Caldwell Zoo's South America section, which will now be called "Amazon's Edge" and will include new jaguar, giant river otter, and sloth habitats.