Born in Amarillo, Texas, Jennings was brought up in Denver, Colorado. Following his graduation from high school, in the late 1930s he moved to Los Angeles which was just becoming the birthplace of the US lesbian and gay rights movement. There his lifelong fascination with stage and screen began to bloom. In Pasadena, he distinguished himself as writer, producer and director.
In 1942 he joined the U.S. Army and was stationed for two years in Guadacanal, a notorious World War II battleground. After being honorably discharged from the Army in 1946, he returned to Los Angeles, studying theatre during a two-year period at the University of Southern California.
In 1950 he was the occasional lover of the student Robert Hull. In November 1950 Robert Hull showed Dale Jennings Harry the Hay's prospectus, Preliminary Concepts. Harry Hay, Rudi Gernreich, Robert Hull, Chuck Rowland, and Dale Jennings met on 11th. and 13th. November to form the Mattachine Society.
It was in 1952 that Jennings mounted, for the very first time, a court challenge to the Los Angeles Police Department's busied enticement and entrapment of gay men. Refusing to back down in the face of acute police intimidation, he became known by fellow activists in the 1950s as "The Rosa Parks of the Gay Rights Movement."
Jennings had been followed home from Westlake Park (which is now MacArthur Park, in Echo Park), Los Angeles, by a plainclothes vice officer who arrested him in his own apartment and charged him with indecent behavior. Demoralized at first, he chose to fight the charge in a previously unheard of course of action.
Doing so, he earned a widespread respect for the newly-formed Mattachine Society, California's first gay-identified organization and, thereafter, because it had formed chapters in Denver, Chicago, and New York, and elsewhere, the first with a national membership.
Members of the Mattachine Society helped him to prepare his defence and he made the unusual choice for the time of opting for a trial by jury. The jury acquitted him, which was a rebuke to the police practice of entrapping homosexuals. Hence he became the first gay man in California to be acquitted of indecent behaviour charges in a police entrapment case.
In the early 1950s, Jennings was one of the co-founders of One Magazine, the first gay publication in the country. In 1954, the postmaster in Los Angeles began confiscating the magazine, claiming it was obscene. This led to another landmark lawsuit, which culminated in a 1958 U.S. Supreme Court ruling that a publication dedicated to equality for homosexuals was not obscene. The decision paved the way for numerous gay and lesbian publications.
In the 1960s, Jennings was a member of The Homosexual Information Center where he sat, with Don Slater on the governing board. "Dale Jennings was a very significant figure in the history of our movement," said William Glover, who had worked side by side with Slater. "He was a giant among the founders of the movement on America's West Coast."
He also wrote three books, and The Cowboys was made into a film starring John Wayne, and then it briefly became a television series. He also published both The Ronin and The Sinking of the Sarah Diamond.
He died of respiratory failure at the age of 82, at Specialty Hospital, La Mirada, California.
