[7] City Park holds the world's largest collection of mature live oak trees, some older than 600 years in age.

New Orleans City Park lost approximately 2,000 trees after Hurricane Katrina and the federal levee failures, but the Dueling Oak still stands where Dueling Oaks Drive meets Dreyfous Drive between the Sydney and Walda Besthoff Sculpture Garden and the New Orleans Museum of Art.

The tract of land, formerly the Allard Plantation, became city property in 1850 through John McDonogh's will and was reserved for park purposes.

This area, to the north of the original park, was actually platted for streets by city planners, though none was ever realized.

This included the installation of many sculptures by WPA artist Enrique Alférez, construction of buildings, bridges, roads, and much of the electrical and plumbing infrastructure that were still serving the park when Hurricane Katrina struck in 2005.

In 1992, Tad Gormley Stadium was remodeled to host the US Olympic Track & Field Trials.

After World War II, two additional 18-hole golf courses were added, I-610 was constructed through the park, a new golf clubhouse was erected, the Wisner Foundation subsidized the development of a scenic parkway running almost the entire length of Bayou St. John (Wisner Boulevard), and multiple rounds of expansion and improvement occurred involving various park facilities.

By the 1970s, City Park featured four 18-hole golf courses, over 50 tennis courts, numerous other athletic fields and facilities, and the newly expanded New Orleans Museum of Art.

[13] Throughout the 1970s, Popp Fountain was the meeting place for the Religious Order of Witchcraft, an occultist coven founded by Mary Oneida Toups.

The subsequent failure of multiple floodwalls brought about the inundation of much of the city, and 95% of the park was flooded with 1 foot (0.30 m) to 10 feet (3.0 m) of water that remained for two to four weeks, damaging all buildings, amusement rides, maintenance equipment, electrical systems and vehicles, and causing the death of more trees and landscaping - including nearly the entire plant collection in the New Orleans Botanical Garden.

[15] As of 2017, City Park is administered and being redeveloped according to its 2005 master plan, the existence of which proved invaluable to the effective channeling of rebuilding assistance in the wake of Hurricane Katrina.

[16] A dedicated bikeway was added between Wisner Boulevard and Bayou St. John for the length of the parkway, another was installed between Bayou St. John and Marconi Drive along the park's northern boundary, and a third was introduced alongside Harrison Avenue.

Most recently, a landscaped walk debuted surrounding Big Lake, adjacent to the New Orleans Museum of Art.

This new amenity, called for in the park's 2005 master plan, has realized the long-held wish of surrounding neighborhoods for a pedestrian- and bicycle-only scenic walk akin to the popular facility long offered in Audubon Park, Uptown.