Garrison first appeared in South Park's pilot episode, "Cartman Gets an Anal Probe", which aired on August 13, 1997.

[1][4] Parker has stated that Garrison has become one of the most complex characters on South Park, particularly due to his relationship with Mr. Hat and his sexuality and gender issues.

"[6] In South Park, Garrison was raised in Arkansas[10] and claims to have a master's degree in mechanical engineering from Denver Community College, as depicted in "The Entity".

Garrison is characterized as being sexually confused, having had both heterosexual and same-sex relationships in addition to two sex reassignment surgeries.

However, in the later episode "Here Comes the Neighborhood", he leads an effort to run affluent residents–who are all Black–out of town using Klan techniques, including burning crosses.

Although the townsfolk at first claim that this is because of the "richers'" wealth, in his last line of the episode, Garrison's intentions are revealed to be indeed racially motivated.

In the episode "An Elephant Makes Love to a Pig", he states that "genetic engineering erases all of God's mistakes, like German people".

It was suggested that Mr. Hat, and his temporary replacement Mr. Twig, were characters through which Garrison could express his repressed gay feelings.

In his absence from teaching, Garrison wrote an erotic romance novel titled In the Valley of Penises, which sold respectably before it won the Gay Pulitzer Prize and was deemed to be "the best work of homoerotic literature since Huckleberry Finn".

In the episodes following the release of his novel, Garrison has a nervous breakdown and flees South Park to become a hermit, where he eventually comes to terms with his gay identity.

The show has implied that Garrison has corprophilic tendencies in "Proper Condom Use", wherein the majority of sexual acts he taught to the kindergarten class involved feces or defecation.

", she attempts to prevent same-sex marriage from becoming legal after finding out that Mr. Slave is engaged to Big Gay Al.

In the following episode, "Go God Go XII", Eric Cartman, having been cryonically frozen 500 years earlier, contacts Garrison's home from the future.

The episode reveals that Garrison was the motivation that convinced Dawkins to teach atheism to the world, and as their relationship ended, the future changed once more.

Unaware of Allison's sexual orientation or growing affection, Garrison unwittingly joins her at a lesbian bar.

After Garrison learns the truth, she is initially shocked but quickly returns Allison's feelings, and the two begin to date.

The episode "Sponsored Content" features Principal Victoria convincing Garrison to return to South Park.

They opined that a direct portrayal of Trump would be dated if the campaign ended quickly, and felt it would be more appropriate to use one of their characters in his role, having already decided Garrison would come into conflict with the new principal.

He realizes that he will be incapable of actually performing his duties as the president if he is elected, and tries to sabotage his own campaign, even outright telling people to vote for Hillary Clinton instead of him.

While his attempts are initially unsuccessful, he eventually manages to lower his poll numbers by making inflammatory comments about women.

After failing to destroy the Member Berries, Garrison makes a speech urging Americans to vote for Clinton in protest of the new film.

Garrison was also intended to play a role in resolving the conflict between the male and female students at the school classroom that had developed over the course of the season, taking responsibility for causing their behavior.

[14] The twenty-first season sees a desperate Garrison returning to South Park after launching a nuclear strike against Canada in "Super Hard PCness".

In the twenty-fifth season, Mr. Garrison started dating a man named Rick in the episode "Pajama Day".

In South Park: Bigger, Longer & Uncut, Satan picks up Mr. Hat as a companion to replace Saddam Hussein.

Mr. Hat is portrayed as racist, as seen in "Chef Goes Nanners", where he is a member of the South Park branch of the Ku Klux Klan.

Garrison rejects this, and Katz is unable to make a counterpoint because he is killed shortly afterward by a gigantic novelty firework.

Parker and Stone have said that the removal of Mr. Hat was symbolic of the show abandoning its original style as a surreal comedy in favor of its current format of satirizing real-life issues and events.