Sergeant Harrison Yates is the South Park police detective and is the leader of the Park County Police Force who is always trying to investigate crime in South Park and is a lot better than Officer Barbrady .
A shaved police officer who is identical to Yates appears working under Lieutenant Dawson in "Lil' Crime Stoppers".
Although never being extremely prominent, he has played a major role in many episodes. In "The Jeffersons", when Michael Jackson (also known as Mr. Jefferson) moves into South Park and it is revealed that Yates hates all black men wealthier than himself and frames them — but panics and becomes disillusioned when he realizes that "Mr. Jefferson" is black despite his "white appearance". He discovers Jefferson is indeed black, but when he decides he will give away all of his money, Yates lets him go, having no need to put another poor black man in jail.
In "Cartman's Incredible Gift", when a serial killer strikes South Park, Yates becomes convinced that Cartman has psychic powers that can capture the killer and dismisses proven science such as fingerprinting and blood analysis as "Hocus Pocus". As a result, he arrests and even kills a number of innocent people based on Cartman's alleged "psychic visions", failing to identify the killer as such when he first investigates him, despite an overabundance of evidence.
In "Miss Teacher Bangs a Boy", Kyle reports to Yates and the cops that the Kindergarten teacher, Ms. Stevenson, is in a relationship with his younger brother, Ike. It is shown that Yates and his pals, like all the other men in South Park do not see anything wrong with women committing sex crimes like this one. At one point remarked that he would have gladly hooked up with a sexed-up teacher when he was a kid, again proving to be more of a hindrance than anything else to the case.
In "Butters' Bottom Bitch", he went undercover as a prostitute after learning of an increase in South Park prostitutes. Though it was obvious when he was a man in drag (he retained his male sexual organs, his mustache and his hairy body), no one seemed to notice this or at least chose to ignore it. He also is unaware of the fact he doesn't need to have sex with the Johns to arrest them for soliciting prostitution, something that creeps out the rest of his squad. He seems to take his role so seriously that he not only has sex with his Johns, he also is involved in a bareback gang-bang with dozens of Alpha Tau Omega fraternity men at the college, and he also "falls in love" with his pimp, runs off to Switzerland, is married for a year, before at last arresting him.
In "The Coon", Yates is the primary police officer approached by Cartman in the guise of the Coon. While he seems to see the Coon as an annoyance and tells him to leave, Yates praises the assistance and work of the town's other hero, Mysterion, despite neither hero doing much to assist the police force themselves and the lack of response by them to either hero.
Yates has orange hair, an orange mustache, and thick, orange eyebrows. He wears a white, button-up shirt, black tie, black suspenders, gold watch, a belt with a gold buckle, and in a brown leather holster his stainless Smith and Wesson 5900-series pistol with wood grips (as does his partner Mitch Murphy, indicating this is most likely the standard issue duty sidearm for South Park PD) As a prostitute, he wore a short, red skirt, a red bra and a blonde wig.
Yates appears to be rather gullible and believes in the supernatural, and often wastes time by conducting extremely trivial investigations. He seems to enjoy letting other people solve crimes for him, be they supposed psychic mediums, the Hardly Boys, Butters Stotch or Mysterion (Kenny). He is also stupid (possibly slightly more so than Officer Barbrady) racist and misogynistic, the last two of which he is perfectly willing to misuse the law to satisfy. Like most other South Park citizens, however, he does not notice these negative traits or rather believes they are good. There is a great possibility that he is a closet homosexual or at least bisexual as depicted in "Butters' Bottom Bitch" where he takes his prostitute role way too seriously. In "Naughty Ninjas" he suggests he "might even kiss a dude" while hula dancing.