Sergeant Harrison Yates (often called Detective Harris) is the lead detective of the Park County Police Force and presumably, the highest-ranked police officer in Park County. He is usually accompanied by his partner Mitch Murphy or generic police officers.
He first appears as a member of the FBI but has since been seen as part of the Park County Police, a role he has consistently kept in the series since then.
In "Christian Rock Hard", he appears as a member of the Federal Bureau of Investigation investigating illegal music downloads online, helping Stan, Kyle and Kenny realize that their downloads are hurting musicians' careers
The character received his formal introduction in "The Jeffersons", where he is first depicted unambiguously as the lead detective in the Park County Police Force, mentioning having served for twenty-five years, with his name being used for the first time, his partner Mitch and his wife Maggie also being introduced. After Michael Jackson (also known as Mr. Jefferson) moves into South Park, he and the other detectives try to frame him as the file claims he is a wealthy black man. He then panics and becomes disillusioned when he sees Jefferson, believing him to be white, and is concerned he may have sent an innocent man to jail who was not black. After a pep talk from his wife, he resumes his investigation, but when Jefferson decides to 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 is desperate for answers and begins turning to psychics. He 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. He does ultimately put this aside and use 'good old fashioned police work' to help apprehend the Left Hand Killer.
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 he 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.
- Marijuana paraphernalia: In "Bike Parade" he is seen smoking cannabis. Though usage of marijuana is legal in the state of Colorado, police officers are prohibited from the usage of this drug.
- Framing Innocent People: In "The Jeffersons" he has mentioned how he and his fellow officers have been framing rich African-Americans for crimes they didn't commit, he even reveals that he has knowledge of how the police framed O.J. Simpson and expressed disappointment that the case fell apart because "one man said the n-word in court". He was about to use false evidence from another police department to arrest Michael Jackson (who in South Park continuity was being framed for child molestation), only to change his mind when Jackson decided to give all his money away making him "another poor black man". He also mentioned earlier in the episode how he aided in the framing of Kobe Bryant.
- Hate Crimes: In "The Jeffersons", since all of the people Yates framed were of African-American descent and he arrested them out of spite for being richer than he is, this is clearly a series of hate crimes, in addition to framing the innocent. Also in"Naughty Ninjas" he and his fellow officers reveal that one of their main motives in joining the force was for the sole purpose of being able to beat up people of minority descent and expressing anguish that in society's eyes it's wrong and he can longer abuse innocent people for no reason. This heavily implies a lengthy history of abuse towards minorities and heavy corruption in Yates' department. The town later sanctions this abuse in order to get rid of many homeless people and drug addicts migrating from the abandoned SoDoSoPa into the more prominent parts of town, allowing them to abuse the vagrants that are of minority descent, satisfying their racist desires. In "The Pandemic Special" during the fight between Cartman and Kyle he shoots Token Black alongside with his partner.
- Police Brutality: In "Naughty Ninjas", following the town sanctioning their persecution of minorities when they happen to be part of the homeless and drug-using vagrants camping out in various parts of town, allowing Yates and his colleagues to maliciously beat said vagrants
- Ignoring/Undermining Serious Crimes: In "Miss Teacher Bangs a Boy" when Harrison learns from Kyle Broflovski under the alias "Brad" that a teacher is having sexual relations with a student (the former being kindergarten teacher Ms. Stevenson and the latter being Kyle's toddler brother Ike), Harrison is initially greatly alarmed and determined to arrest the pedophile, but upon learning that the teacher is in fact an attractive young woman, he sees no issue with this and doesn't even view this as child molestation, only feeling jealous that a toddler is having sex with her and not him. Later however he does arrest and charge her but he actually apologizes to her saying the "lady principal" insisted, with this and his evident bias shown above it is proven that he is misogynistic.
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. His microscopic intelligence is showcased when it took him (presumably) hours of extensive research to understand that a left-hand remains as such, regardless of the angle of which it's seen.
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 and marries his pimp in order to arrest him. In "Naughty Ninjas" he suggests he "might even kiss a dude" while hula dancing.
He is married to Maggie Yates, who shares his views on rich black men, as she supported him in "The Jeffersons". She is very supportive and encouraging towards him throughout her appearances in later episodes. Ironically, in "Butters' Bottom Bitch" he engages in a long-term affair with a wealthy black man, Keshawn, citing him to be his "pimp".
He has an unnamed son, mentioned in "Cartman's Incredible Gift" as enjoying cutting women's faces out of photographs.
Yates appears in the police office as a "friendable" friend. He sends the player to collect five rings from the Nazi zombies. When the player collects the rings, Yates befriends him. Yates cannot be befriended when the Nazi zombies disappear.
Sergeant Yates has a bigger role in The Fractured But Whole as he works under Mitch Conner. He gives the New Kid two successive missions on the second day: Operation Just 'Cause and Operation Blind Justice, both of which are about arresting black people for apparently no reason. After completion, he becomes the New Kid's Coonstagram follower.
His prominent role in this game takes place during The Thin White Line mission. As the New Kid fights further into the police station, he consistently tries to explain that he is not a racist. After all the horrible truth turns out to be, that Yates and his fellow cops are Outer-God worshipers. He engages himself in the bossfight against Shub-Niggurath, and is beatable.
Yates also appears in Danger Deck as an enemy.
- "Christian Rock Hard" - Shows Stan, Kyle, and Kenny what happens to famous people who download their music.
- "Casa Bonita" - Tries to find Butters and arrests Eric Cartman for Butters' abduction.
- "The Jeffersons"
- "Cartman's Incredible Gift" - Works with Eric Cartman and Kyle Broflovski to solve numerous murders.
- "The Death of Eric Cartman" - Talks to the escaped convicts who are holding people hostage.
- "Mr. Garrison's Fancy New Vagina" (shaved esque re-appears)
- "Free Willzyx" - Tries to solve the disappearance of a whale which The Boys stole after they thought the whale could talk.
- "Mystery of the Urinal Deuce"
- "Miss Teacher Bangs a Boy" - Investigates a sexual relationship between Ike Broflovski and Ms. Stevenson.
- "Cartman Sucks" - Cartman goes to him when he cannot find a picture of him and Butters.
- "Britney's New Look" (background) - Seen taking photos of Britney Spears along with many other people.
- "Eek, A Penis!" - Helps Mr Garrison find his penis.
- "The China Probrem" - Refuses to pursue the Indiana Jones and the Kingdom of Crystal Skull case because he has not seen the film.
- "The Coon"
- "Butters' Bottom Bitch" - Seen going undercover as a prostitute, after learning about a prostitution ring forming in South Park.
- "Medicinal Fried Chicken" (background) - Seen while Officer Barbrady gives a speech.
- "It's a Jersey Thing" (background)
- "Royal Pudding" - Tells Mr. Mackey that tooth decay is gone.
- "City Sushi" - Tells Stephen Stotch that his son caused a war between City Wok and City Sushi.
- "A Nightmare on Face Time" - Investigates a robbery with the help of Stan Marsh.
- "Informative Murder Porn" - He and other police officers investigate the murder of a woman.
- "The Magic Bush" - Thomas Tucker and Laura Tucker go to him to get the drone issue under control.
- "Cock Magic" - He was called Detective Harris in this episode.
- "#HappyHolograms" - He was also called Detective Harris in this episode.
- "The City Part of Town"
- "You're Not Yelping" - Goes overboard with yelper reviews.
- "Naughty Ninjas" - He and the rest of the South Park Police refuse to enforce the law after Officer Barbrady is fired.
- "PC Principal Final Justice"- Seen in the crowd of people standing in front of the Whole Foods Market.
- "Not Funny" - Seen giving a press conference to the people of South Park about the impending dangers of TrollTrace.com.
- "Franchise Prequel" - He insists that the townspeople cannot with Mark Zuckerberg invading people's homes, riding their vehicles, as well as eating their food when never breaks the law.
- "Sons A Witches" - Talks to Eric Cartman about the kidnapping of Heidi Turner.
- "Dead Kids" - Seen outside the school after the shooting.
- "A Boy And A Priest" - Seen in church.
- "The Problem with a Poo" - Seen outside after another school shooting.
- "The Scoots" - Holds a meeting in the Park County Community Center.
- "Time To Get Cereal" - Mistakes ManBearPig's attacks with school shootings and gets annoyed by not playing Red Dead Redemption II.
- "Nobody Got Cereal?" - Continue his investigations on ManBearPig attacks. Comes to the conclusion that he must believe in ManBearPig.
- "Bike Parade" - Seen smoking and watching the bike parade with the other officers.
- "Tegridy Farms Halloween Special" - Investigates what is happening at Tegridy Farms after Randy Marsh makes a report there.
- "Turd Burglars" - is explained to him by Dr. Gauche that half of South Park's citizens are sick with bacteria from their mothers.
- "The Pandemic Special" - Becomes the substitute teacher of the 4th-grade class; tries to control the riots happening and maintain peace and order.
- "South ParQ Vaccination Special" - Seen at the end celebrating the end of the pandemic.
- In "Cartman's Incredible Gift", Yates is called Lou at one point. He is also sometimes called Detective Harris, which is the name Trey uses in scripts. The name Harrison Yates was restored in "You're Not Yelping", but he still often recurs to Harris.
- His undercover name was Yolanda in "Butters' Bottom Bitch".
- Like all police officers in South Park, Yates hates wealthy African-Americans.
- However, he seems to have no issue with their race when they are poor.
- In "The Coon", Yates essentially plays the role of Commissioner Gordon to Cartman's super-hero identity, The Coon, and to Kenny's super-hero identity, Mysterion.
- Yates was originally shown working for the FBI in "Christian Rock Hard" and then the South Park Police Department in "Casa Bonita". He was also shown handling a case in Denver in "Free Willzyx".
- His voice is usually identical to Lieutenant Dawson's from "Lil' Crime Stoppers".
- Yates shoots Michael Deets twice in the face. A detective in "Miss Teacher Bangs a Boy" claims to have shot a man in the face twice, possibly taking credit for Yates' deed.
- Yates has spoken in every season since his introduction in Season Seven.
- He and Officer Barbrady were never seen together between "Casa Bonita" and "Medicinal Fried Chicken", and never interacted onscreen until "The City Part of Town", after co-existing for over a decade. They seem to be on friendly terms.
- In the commentary for Season Nineteen, Trey suggests the introduction of Yates and his police department, and the phasing out of Officer Barbrady was an intentional choice, as they felt Barbrady was no longer in line with comedy after the nineties.