He eventually launched a theater company called the Theatre Caravan, located in a now demolished building near Olympic Blvd.
In November 1950, Jennings accompanied his then-boyfriend Bob Hull, to a meeting with Harry Hay and Chuck Rowland to discuss a prospectus that had called on the “androgynies of the world” to unite.
The group began to grow and by the summer of that year they had adopted official missions and purposes which proclaimed homosexuals to be one of the largest minorities in America.
Jennings called fellow Mattachine founder Harry Hay, and they enlisted the help of attorney George Sibley, a member of the Citizens' Council to Outlaw Entrapment.
While there were different accounts of what exactly occurred that day, by the end of the trial the jury voted 11–1 for acquittal[10] on the basis of police intimidation, harassment, and entrapment of homosexuals, and the case was dismissed.
Jennings was elected as vice president of the newly formed organization and became editor in chief as well as a primary writer for the magazine.
The magazine included writings about police harassment and persecution from cities all across the nation based on newspaper reports sent in by its readers.
[12] After leaving ONE, Jennings wrote and published his first novel, The Ronin,[13] retold from an ancient Buddhist story, followed by The Sinking of the Sarah Diamond.
[14] Another book, The Cowboys,[15] based on a film treatment he sold to Warner Bros., caused considerable controversy among publishers due to its glimmers of homoeroticism.
After losing his home due to a lawsuit with a former lover he moved to the town of Trinidad in Humboldt County in northern California where he decided to re-involve himself in the movement.
Around this time Jennings began losing his memory and constantly worried that his writings would be lost, so he made arrangements that his works and property would go to the HIC when he died.
He continued to write until shortly before his death on May 11, 2000, at the age of 82 at Specialty Hospital in La Mirada, California; he is survived by one nephew.
His legacy to the HIC consists of hundreds of articles, including unpublished books, plays, film treatments and stories.