Wirt is the older half-brother of Gregory. He is the protagonist of the show, and views the world in a serious way, unlike his brother. He is determined and makes a point of being in opposition to the others' suggestions, which often leads them into trouble. He is voiced by Elijah Wood.
Wirt is a relatively tall and rather thin boy, with a red pointed gnome hat made from an old Santa hat. His outfit consists of a navy blue cape with yellow buttons, simple grey pants that reach his ankles, suspenders, and a classic buttoned up white shirt. His hair is dark brown with pointed bangs that cover the majority of his forehead. He has large ears, a pointy nose and and big, round eyes with black pupils. He wears two different types of shoes, his left shoe being dark gray/brown and the other being black. They are commonly left untied, a noticeable trait throughout the series.
In the episode Into the Unknown, it is revealed that Wirt's outfit is merely a Halloween costume. His normal attire consists of an earth-toned sweater that he wears over a collared white shirt and ordinary gray slacks, possibly the same pants that he wore with his costume. Without his hat on, Wirt's hair takes on a rather messy appearance.
Wirt is a pessimistic realist in many ways, but also has a naïve and childish side to him. He is easily scared and surprised, and even though he is far more perceptive than his brother, he is very much still a kid. Throughout the storyline of Over the Garden Wall, Wirt has to struggle to remain optimistic against impossible odds. In chapter eight, Babes in the Woods, Wirt finally begins to succumb to his hopelessness and gives up on the notion that he and his brother will ever escape the Unknown. His tendency to think negatively is what made him an easier target for the Beast to drag down into despair. Wirt's brother, Gregory, is a parallel of his brother that pulls out the playful, jovial, childlike side of Wirt.
In chapter nine, Into the Unknown, Wirt is shown to have low self-esteem and that he perceives himself to be an outcast, possibly due to his more sensitive interests like poetry and interior design. He tells Greg that he cannot enter the Halloween party because he was not invited and that his crush Sara is interested in Jason Funderberker, a terribly awkward yet good-natured boy whom he considers a threat. However, both of these statements are later shown to be false— a result of his insecurities causing him to distort the reality.
Wirt seems to be the type of teenager that makes out everything to be worse than it actually is, as shown in chapter nine multiple times; his overreaction to Greg giving the tape to the girls during the football game, the fact that Sara's friends and everyone at the party seems to know him and consider him a friend (despite his belief that he is a social outcast), and his meltdown over the cassette tape unintentionally falling into Sara's possession. He claims that his life is ruined when this happens, blames Greg, and refuses point-blank to simply talk to Sara about his feelings, which ultimately further complicates both his interactions with her and his eventual predicament in the Eternal Garden. It is demonstrated in his confrontation with the Beast that when Wirt critically analyzes his predicaments and remains considerate of others, he is able to calmly and confidently reach a solution, whereas before he was so overwhelmed with anxiety and uncertainty that coming up with worse-case scenarios was but the only thing he could do. In these situations Wirt was prone to lethargy, melodramatic, displaced anger and a tunnel vision focus on his problems.
By the end of the series Wirt seems to have matured, having found the strength to stand up to the Beast and escape the Unknown while also having accepted his responsibility as a brother.
- Wirt is also the main protagonist of Tome of The Unknown.
- Wirt was one of the first characters to be seen in a short preview as part of a sales video by Cartoon Network in June 2013.
- Wirt is overly cautious of many things, and prefers to be by himself. However, he has Gregory to look after.
- His secret passions are poetry and playing the clarinet.
- The name means "worthy" or "powerful" and "strong".
- Wirt, along with Greg and the frog, may appear to be from the year the setting takes place, but in fact he appears to be from the late 20th century, still wearing his costume before he and Greg got lost on Halloween. Sometimes it was hinted throughout his remarks, reasoning and knowledge seemingly out of place of that era.
- Making cassette tapes for significant others was a popular pastime in the late 70s and 80s (almost to a cliche point).
- Judging from how Sara states that she does not own a cassette tape player, one can infer that the story takes place in a modern setting.
- In one of concept art Wirt's original name was Walter. This may be unintentional, but his name makes a pun out of the phrase 'Worry Wart', aptly capturing Wirt's disposition.
- The cape he wears is a WWII nurse cape.
- Wirt's hat is made from what looks like a Santa hat with the fuzz cut off.
- The shot of Wirt's room in "Into the Unknown" shows that he owns a book on interior design, which explains how Wirt recognized the difference in architecture of the two mansions in episode 5, "Mad Love".
- Wirt can play the bassoon quite well, as shown in "Lullaby in Frogland."