Trey Parker

Following his graduation from high school in 1988, Parker spent a semester at Berklee College of Music before transferring to the University of Colorado at Boulder. During his time there, he took a film class in which students were required to collaborate on projects. In the course, he met Matt Stone—a math major from the nearby town of Littleton—and the two immediately bonded over provocative, anti-authoritarian humor and Monty Python. Parker's first film was titled Giant Beavers of Southern Sri Lanka (1989), parodying Godzilla-style rampages with beavers; fellow student Jason McHugh later remarked that the idea nearly got him laughed out of class. Parker and Stone wrote and acted in many short films together, among those First Date, Man on Mars and Job Application. Parker later remarked that he and Stone would shoot a film nearly every week, but he has since lost most of them. Parker first used a construction paper animation technique on American History (1992), a short film made for his college animation class. It became an unexpected sensation, resulting in Parker's first award—a Student Academy Award. Parker recalled sitting in the auditorium in front of students from animation schools such as CalArts, saying:

In 1992, Parker, Stone, McHugh, and Ian Hardin founded a production company named the Avenging Conscience, named after the D. W. Griffith film by the same name, which all four actively disliked. Parker again employed the cutout paper technique on Avenging Conscience's first production, Jesus vs. Frosty (1992), an animated short pitting the religious figure against Frosty the Snowman.

Alferd Packer: The Musical premiered in Boulder in October 1993; "they rented a limousine that circled to ferry every member of the cast and crew from the back side of the block to the red carpet at the theater's entrance." The group submitted the film to the Sundance Film Festival, who did not respond. Parker told McHugh he had a "vision" they needed to be at the festival, which resulted in the group renting out a conference room in a nearby hotel and putting on their own screenings. MTV did a short news segment on The Big Picture regarding the film, and they made industry connections through the festival. They intended to sell video rights to the film for $1 million and spend the remaining $900,000 to create another film. The film was instead sold to Troma Entertainment in 1996 where it was retitled Cannibal! The Musical, and upon the duo's later success, it became their biggest-selling title. It has since been labeled a "cult classic" and adapted into a stage play by community theater groups and even high schools nationwide.

At the time, Comedy Central had a low distribution of just 21 million subscribers. The company marketed the show aggressively before its launch, billing it as "why they created the V-chip." The resulting buzz led to the network earning an estimated $30 million in T-shirts sales alone before the first episode was even aired. South Park premiered in August 1997 and immediately became one of the most popular shows on cable television, averaging consistently between 3.5 and 5.5 million viewers. The show transformed the fledgling network into "a cable industry power almost overnight." Due to the success of the series' first six episodes, Comedy Central requested an additional seven; the series completed its first season in February 1998. An affiliate of the MTV Network until then, Comedy Central decided, in part due to the success of South Park, to have its own independent sales department. By the end of 1998, Comedy Central had sold more than $150 million worth of merchandise for the show, including T-shirts and dolls. Over the next few years, Comedy Central's viewership spiked largely due to South Park, adding 3 million new subscribers in the first half of 1998 alone, and allowed the network to sign international deals with networks in several countries.

Parker and Stone signed a deal with Comedy Central in April 1998 that contracted the duo to producing South Park episodes until 1999, gave them a slice of the lucrative spinoff merchandising the show generated within its first year, as well as an unspecified seven-figure cash bonus to bring the show to the big screen, in theaters. During the time, the team was also busy writing the second and third seasons of the series, the former of which Parker and Stone later described as "disastrous". As such, they figured the phenomenon would be over soon, and they decided to write a personal, fully committed musical. Parker and Stone fought with the MPAA to keep the film R-rated; for months the ratings board insisted on the more prohibitive NC-17. The film was only certified an R rating two weeks prior to its release, following contentious conversations between Parker/Stone, Rudin, and Paramount Pictures. Parker felt very overwhelmed and overworked during the production process of the film, especially between April and the film's opening in late June. He admitted that press coverage, which proclaimed the end of South Park was near, bothered him. South Park: Bigger, Longer & Uncut opened in cinemas in June 1999 and received critical acclaim while grossing $83 million at the box office.

South Park has continued, becoming an enterprise worth hundreds of millions of dollars. The franchise has also expanded to music and video games. Comedy Central released various albums, including Chef Aid: The South Park Album and Mr. Hankey's Christmas Classics, in the late 1990s. The song "Chocolate Salty Balls" (as sung by the character Chef) was released as a single in the UK in 1998 to support the Chef Aid: The South Park Album and became a number one hit. Parker and Stone had little to do with the development of video games based on the series that were released at this time, but took full creative control of South Park: The Stick of Truth, a 2014 video game based on the series that received positive reviews and for which they shared (with Eric Fenstermaker) the 2014 Writing In A Comedy and Parker won the Performance in a Comedy, Supporting award by National Academy of Video Game Trade Reviewers (NAVGTR). Broadcast syndication rights to South Park were sold in 2003, and all episodes are available for free full-length on-demand legal streaming on the official South Park Studios website. In 2007, the duo, with the help of their lawyer, Kevin Morris, cut a 50-50 joint venture with Comedy Central on all revenue not related to television; this includes digital rights to South Park, as well as films, soundtracks, T-shirts and other merchandise, in a deal worth $75 million.

In 2000, Parker and Stone began plotting a television sitcom starring the winner of the 2000 presidential election. The duo were "95 percent sure" that Democratic candidate Al Gore would win, and tentatively titled the show Everybody Loves Al. Parker said the producers did not want to make fun of politics: the main goal was to parody sitcom tropes, such as a lovable main character, the sassy maid, and the wacky neighbor. They threw a party the night of the election with the writers, with intentions to begin writing the following Monday and shooting the show in January 2001 with the inauguration. With the confusion of who the President would be, the show's production was pushed back. The show was filmed at Sony Pictures Studios, and was the first time Parker and Stone shot a show on a production lot.

Although That's My Bush!, which ran between April and May 2001, received a fair amount of publicity and critical notice, according to Stone and Parker, the cost per episode was too high, "about $1 million an episode." Comedy Central officially cancelled the series in August 2001 as a cost-cutting move; Stone was quoted as saying "A super-expensive show on a small cable network...the economics of it were just not going to work." Comedy Central continued the show in reruns, considering it a creative and critical success. Parker believed the show would not have survived after the September 11 attacks anyway, and Stone agreed, saying the show would not "play well". During this time, the duo also signed a deal with Macromedia Shockwave to produce 39 animated online shorts in which they would retain full artistic control; the result, Princess, was rejected after only two episodes.

In 2002, the duo began working on Team America: World Police, a satire of big-budget action films and their associated clichés and stereotypes, with particular humorous emphasis on the global implications of the politics of the United States. Starring puppets, Team America was produced using a crew of about 200 people, which sometimes required four people at a time to manipulate a marionette. Although the filmmakers hired three dozen highly skilled marionette operators, execution of some very simple acts by the marionettes proved to be very difficult, with a simple shot such as a character drinking taking a half-day to complete successfully. The deadline for the film's completion took a toll on both filmmakers, as did various difficulties in working with puppets, with Stone, who described the film as "the worst time of [my] life", resorting to coffee to work 20-hour days and sleeping pills to go to bed. The film was barely completed in time for its October release date, but reviews were positive and the film made a modest sum at the box office.

Politically, Parker describes himself as libertarian, as does his partner Matt Stone. In 2004, Parker summed up his views with the comment:

Parker and Stone, alongside writer-composer Robert Lopez, began working on a musical centering on Mormonism during the production of Team America. Lopez, a fan of South Park and creator of the puppet musical Avenue Q, met with the duo after a performance of the musical, where they conceived the idea. The musical, titled The Book of Mormon: The Musical of the Church of Jesus Christ of Latter-day Saints, was worked on over a period of several years; working around their South Park schedule, they flew between New York City and Los Angeles often, first writing songs for the musical in 2006. Developmental workshops began in 2008, and the crew embarked on the first of a half-dozen workshops that would take place during the next four years. Originally, producer Scott Rudin planned to stage The Book of Mormon off-Broadway at the New York Theatre Workshop in summer 2010, but opted to premiere it directly on Broadway, "[s]ince the guys [Parker and Stone] work best when the stakes are highest."

Parker married Emma Sugiyama in 2006. The officiant was 1970s sitcom producer Norman Lear. The marriage ended through divorce in 2008. Parker subsequently began a relationship with Boogie Tillmon, whom he later married in 2014. The marriage gained Parker a stepson. Their daughter, Betty Boogie Parker, was born in 2013. The couple divorced in 2019, citing irreconcilable differences.

After a frantic series of rewrites, rehearsals, and previews, The Book of Mormon premiered on Broadway at the Eugene O'Neill Theatre on March 24, 2011. The Book of Mormon received broad critical praise for the plot, score, actors' performances, direction and choreography. A cast recording of the original Broadway production became the highest-charting Broadway cast album in over four decades. The musical received nine Tony Awards, one for Best Musical, and a Grammy Award for Best Musical Theater Album. The production has since expanded to two national tours, a Chicago production, UK production, and as of 2014 Parker and Stone had confirmed that a film adaption was in pre-production.

Parker and Stone continue to write, direct, and voice most characters on South Park. Over time, the show has adopted a unique production process, in which an entire episode is written, animated and broadcast in one week. Parker and Stone state that subjecting themselves to a one-week deadline creates more spontaneity amongst themselves in the creative process, which they feel results in a funnier show. Although initial reviews for the show were negative in reference to its crass humor, the series has received numerous accolades, including five Primetime Emmy Awards, a Peabody Award, and numerous inclusions in various publications' lists of greatest television shows. Though its viewership is lower than it was at the height of its popularity in its earliest seasons, South Park remains one of the highest-rated series on Comedy Central. In 2012, South Park cut back from producing 14 episodes per year (seven in the spring and seven in the fall) to a single run of 10 episodes in the fall, to allow the duo to explore other projects the rest of the year. As of 2019 the show is renewed through 2022, when it will reach its twenty-sixth season. The show's twenty-third season premiered on September 25, 2019.

With sufficient funds from their work on South Park and The Book of Mormon, the duo announced plans to create their own production studio, Important Studios, in January 2013. The studio will approve projects ranging from films to television to theatre.

On April 13, 2016, Universal Pictures announced that Trey Parker would be voicing the villain Balthazar Bratt in Despicable Me 3. The film, released in June 2017, was Parker's first voice role not scripted by either himself or Matt Stone.