During his tenure as chief many significant events occurred that would shape Los Angeles during the decade of the 1940s, when the population of the city proper surged from 1.5 million to nearly 2 million people. Events such as World War II, Japanese-American relocation and internment (see Japanese American internment), the Zoot Suit Riots of 1943 and the Black Dahlia homicide roiled the city, as did the Brenda Allen vice scandal of 1948–49 that led to Chief Horrall's resignation after it was found that officers involved with the Hollywood madam perjured under oath during grand jury testimony, as did Horrall himself. He resigned in 1949.
When Jack Webb's radio program Dragnet commenced in 1949, Horrall's endorsement of the program was acknowledged at the end of every episode. That tradition continued with W. A. Worton and continued throughout the various spin offs of Dragnet.
In the 2011 Team Bondi video game L.A. Noire, the Chief of Police in that game is based on Clemence B. Horall.