In 1878, James W. Beardsley, a wealthy farmer, donated over 100 acres (40 ha) of hilly, rural land bordering on the Pequonnock River, with a distant view of Long Island Sound, to the city of Bridgeport on the condition that "the city shall accept and keep the same forever as a public park".

[5] Olmsted described the existing land as "pastoral, sylvan and idyllic" and, in 1884, delivered his plan for a simple, rural park for the residents to enjoy:[6][The land donated by Beardsley] is thoroughly rural and just such a countryside as a family of good taste and healthy nature would resort to, if seeking a few hours' complete relief from scenes associated with the wear and tear of ordinary town life...

The object of any public outlay upon it should be to develop and bring out these distinctive local advantages, and make them available to extensive use in the future by large numbers of people.Olmsted was the principal architect of the site.

In 1909, the city erected a statue created by Charles Henry Niehaus in honor of Beardsley at the park's Noble Avenue entrance.

Barnum would exercise his animals through the streets of Bridgeport, and people gathered in Beardsley Park to see zebras and camels walking by.

By 1927, the zoo had acquired a variety of exotic animals, including a camel donated by the Barnum and Bailey Circus.

The society continues to run the zoo as a private, nonprofit institution with assistance from the state of Connecticut and the city of Bridgeport.

On March 31, 2012, the zoo and DEEP held another amnesty day, this time only aiming to accept animals which were illegal to own in Connecticut or that were in very bad condition.

[11][12] In January 2010, the oldest Andean condor in the world, Thaao, died at the zoo after being a resident for 17 years.

The Victorian Greenhouse is also home to two agave plants that have grown flower stalks, and are expected to bloom soon as of January 2020.

[37] At the entrance, a pair of brick buildings that once served as trolley barns for the city of Bridgeport now hold administrative offices.

Species the zoo has contributed to the reintroduction of include red wolves, golden lion tamarins, Andean condors, and brook trout.