One of the pioneer folklore collectors during the first half of the 20th century, he is remembered for having infiltrated the Ku Klux Klan in the 1940s, exposing its secrets to authorities and the outside world.

[2] His views on race relations in the South were largely influenced by his family's black maid, known only as "Flo", whom Kennedy considered "almost like a mother".

[5] He recalled that during his childhood in the 1920s, local Klan members beat and raped Flo for "sassing whitefolks" after she questioned a white bus driver who had given her incorrect change.

Recalling this incident later in life, Kennedy said, "At a very tender age, I became aware that grownups were lying about a whole lot more than Santa Claus", in reference to the Klan's claims of being Christian patriots.

As part of the Federal Writers' Project, the Library of Congress hired archivists to document the diversity of American culture by recording regional folksongs (e.g., children's songs, dance and gospel music) and oral histories in many languages and dialects.

[12] Kennedy relied on unused material collected during his time with the Federal Writers' Project for his first book, Palmetto Country (1942).

He wrote a series of monographs objecting to racist policies like poll taxes and white primaries because they were designed to disenfranchise minorities and poor people.

[14]: 281  Because his bad back disqualified him for service in World War II, he decided to channel his patriotism towards combating racial injustices in the Jim Crow South.

[15]: 22–4  Using Talmadge as a reference, Kennedy secured a sales job with the racist magazine The Southern Outlook and managed to join the Nathan Bedford Forrest Klavern #1 of the KKK.

[15]: 32–3 With the help of other informants, Kennedy filed detailed reports on the Klavern's Monday night meetings from September 1944 until November 1948.

[10]: 192  He also reported the Klan's various crimes to the Georgia Bureau of Investigation, the FBI, as well as police, prosecutors, journalists, and human rights organizations.

He also relished the absurd flourishes of Klan lore, such as making "K" the initial letter for most terms, renaming the days of the week "Dark, Deadly, Dismal, Doleful, Desolate, Dreadful, and Desperate", and their byzantine handbook the Kloran.

In 1944, he was pitching a similar book organized around Roosevelt's Four Freedoms, but it took another two years of revisions to convince Doubleday to publish Southern Exposure.

[10]: 215  Having once called the KKK "an old American institution" after allowing Imperial Wizard James A. Colescott to testify, HUAC was uninterested in Kennedy's information.

The Klan was irate to hear its machinations made public, such as Eugene Talmadge's secret promise to appoint the KKK's Atlanta Cyclops to run the Georgia Bureau of Investigation.

[14]: 289 On June 10, 1946, the highly popular Adventures of Superman radio show began a 16-episode story called "The Clan of the Fiery Cross".

[22] In The New Republic, Thomas Whiteside described Superman's regular use of KKK passwords as a constant irritant to Grand Dragon Samuel Green, who was forced to listen to the show and update compromised codes.

[21]: 147 In early 1947, Stetson Kennedy's undercover career as John Perkins ended when he was subpoenaed to testify in the trial of Homer Loomis and Emory Burke.

Writing in the style of Mickey Spillane, Kennedy is a hard-boiled witness to everything from the murder of a Black man by the KKK to the "Wool Hat Putsch" by Herman Talmadge.

"[33] His first marriage was in 1936 to Edith Ogden-Aguilar,[6] a Cuban émigré he met in Key West, Florida while doing fieldwork for his own writing shortly after leaving UF.

[36] In 2006, at 90 years old, Kennedy married writer and bookstore owner Sandra Parks, a former city commissioner of St. Augustine, Florida.

[1] In 2003, Friends of Libraries USA put Beluthahatchee on its national register of literary sites and, to commemorate the occasion, Arlo Guthrie gave a concert in Jacksonville.

The Park's perimeter is surrounded by a heavy canopy of native vegetation and the enclave provides a habitat for wildlife and continues to serve as a rookery and roosting place for many types of waterfowl and other birds.

A log cabin that's in the park may serve as a caretaker residence while the fourth building there may house an Artist-in-Residence through the Florida Folklife program.

[42] The park is part of a 70-acre tract that Kennedy purchased in 1948, recorded restrictive covenants setting aside land in perpetuity as a wildlife refuge, and the following year subdivided, subsequently selling all but his own 4 acre parcel.

[40] Kennedy died on August 27, 2011, at Baptist Medical Center South in Jacksonville, Florida, where he had been in palliative care for several days.