Percy Green

Green was subsequently hired to direct the minority and women-owned business utilization program. Under the administration of Mayor Freeman Bosley, Jr., Green oversaw the certification process and used that oversight to make sure certifications were not given to "front" businesses (where a woman or minority poses as the owner of a business that is actually run by a white man). He was retained in that position by the administration of Mayor Clarence Harmon, but his role was reduced to certification. Green was terminated by incoming Mayor Francis Slay in 2001.

On July 14, 1964, Green and Richard Daly, a white college student, scaled the Gateway Arch to protest the exclusion of blacks from federal contracts and jobs related to the construction of the Arch. Green, Daly, and protesters on the ground demanded that MacDonald Construction Company, the contractor responsible for constructing the Arch, raise the number of African Americans employed on the project to 10% within 10 days. Green and Daly were charged with trespassing and other offenses. Today, a photo of Percy Green hangs inside the Arch in a display commemorating the Arch's history. This incident was one of several that inspired the United States Department of Justice to file the first pattern or practice case against AFL–CIO under Title VII of the Civil Rights Act of 1964.

Along with other members of ACTION, Green was involved in one of the city of St. Louis's most famous civil rights actions: a protest against the Veiled Prophet Ball. The Veiled Prophet Ball was an annual dance that had been held in December every year since 1878. The exclusivity of the ball was part of its appeal to St. Louis elite, but also the cause of different protests over many decades. By the 1960s, the ball—from which membership both Jews and African Americans were denied entry—was the target of Civil Rights protests led by ACTION and others. In December 1972, with the cooperation of several sympathetic debutantes, ACTION infiltrated the Veiled Prophet Ball and unmasked its symbolic head, the mysteriously hooded "Veiled Prophet." Once inside, ACTION member Jane Sauer created a distraction by dropping pamphlets near the stage while fellow member Gina Scott maneuvered behind the "Prophet" and snatched the hood from his head. Multiple witnesses confirmed that the Veiled Prophet was John K. Smith, a Vice President at Monsanto Corporation. "We thought that [the organization] was racist, sexist & elitist," Green later said. "If the city was going to truly integrate, they should not have a Ku Klux Klan-ish event. That’s why we attacked it." ACTION disbanded in 1985.