These characters appear in the American animated television series Regular Show, created by J. G. Quintel for Cartoon Network.

The series revolves around the daily lives of two friends, Mordecai (a blue jay), and Rigby (a raccoon). They work as groundskeepers at a park, and spend their days trying to avoid work and entertain themselves by any means. This is much to the chagrin of their supervisor Benson (a gumball machine) and their coworker Skips (a yeti), but to the delight of Pops (a lollipop). Their other coworkers include a pig-nosed green humanoid nicknamed Muscle Man (real name Mitch Sorrenstein), and a ghost nicknamed Hi-Five Ghost (real name not mentioned in the show).

Mordecai (voiced by J. G. Quintel) is a 6'0" 23-year-old anthropomorphic blue jay who works as a groundskeeper at The Park. He has been best friends with Rigby ever since childhood. Mordecai is more conscientious, intelligent, responsible, and mature about his actions than Rigby is, which sometimes leads to him opposing Rigby when he is the cause of some kind of chaotic problem, albeit unintentionally. Even though Mordecai dislikes his job, he is often willing to put up with it begrudgingly as opposed to Rigby, who is more open about his hatred towards his job and prone to avoid work as much as possible. However, Mordecai usually sides with his friend, occasionally going along with Rigby's attempts to get out of work and the two generally stick together through their adventures.

Mordecai loves to play video games and in most cases is a better player than Rigby, he also demonstrates decent strength, such as carrying large boulders, fighting the death bear, never getting hurt by Rigby's punches, and being able to punch Rigby across an entire room with ease. He can sometimes become caught up in his emotions, often letting them get the better of him. However, he is usually quick to apologize to others if he has hurt them and most of the time takes the lead in fixing a situation.

Mordecai's romantic life is the subject of several episodes, particularly his crush on Margaret Smith, a red-breasted robin who worked as a waitress at a local coffee shop. Mordecai would often hang out with her, along with Rigby and Eileen Roberts. Mordecai had many failed attempts at starting a relationship with her due to either his own nerves or Margaret having a boyfriend at the time. He attempts to date other people in "Yes Dude Yes" and meets CJ. Though the two have a lot in common they part ways at the end of the episode. Mordecai and Margaret finally begin to date in the fourth season until Margaret decides to leave for college, thus ending their relationship and causing Mordecai to go into a brief depression.

Mordecai later bumps into CJ at a New Year's Eve party and they start dating soon after. CJ and Mordecai's relationship is strained due to CJ seeing Mordecai and Margaret having fun together on several occasions as she returned from college. He eventually decides to take a break from dating in "Dumped at the Altar", after his relationship with CJ didn't work out.

In the episode "Camping Can Be Cool", it is revealed that he attended art school before being employed at The Park; however, he did not finish school due to his bad portrait skills, which were revealed in the episode "Bad Portrait". He is shown to have an outgoing mom, who embarrasses him around his girlfriends and also made a highlight reel of Mordecai's most embarrassing moments, as seen in "Maxin' and Relaxin'".

In the epilogue to "A Regular Epic Final Battle", Mordecai quits The Park, parts ways with Rigby, moves to New York City, and returns to making art. He opens a successful exhibition and meets a bat woman whom he eventually marries and starts a family. Mordecai's wife was not given a name in the show. Head writer Matt Price, on Reddit, gave her the name Stef when asked about it, and writer Owen Dennis stated on Tumblr that there had not been previous plans to give a name to the character.