He wears a Miyabigaoka uniform and a beanie which covers his eyes. He also wears headphones around his neck. His hair is black, and his eye color is unknown due to the fact that his eyes are always hidden by his beanie. However, his right eye was shown while talking to Kaon at Maid Latte.
He mainly acts as the cool head to his sister’s quick temper, being the only one who can calm her down and encourages her to try new things. While Kaon takes her responsibilities seriously, he’s known to slack of do to his lack of competitive spirit. Nonetheless, he takes the goal of being Takumi’s friend seriously and unlike Kaon, will not be stopped by his uncooperativeness. He seems to enjoy tormenting his sister.
As Takumi Usui first enters Class 3-A and sees the Elite Group waiting for him, Tomu quickly confronts Hirofumi Koganei, who followed Takumi, asking if he's his friend. Upon finding out that he's not, nor is he of outstanding birth, Tomu disregards him as an outsider. Tomu is identified to be part of the Elite Group at Miyabigaoka, a group of students who have very rich and powerful families. The Elite Group is asked by Tora Igarashi, Miyabigaoka's Student Council President, to befriend Takumi when he arrives at the school. As Takumi receives a call on his phone, Tomu tells him to answer it and stands perplexed with the rest of the group as he hears a voice shout at Takumi. As the talk between the two gets even mushier, Tomu continues listening with a surprised face.
When his sister Kaon Umekōji takes the phone from Takumi and begins to introduce herself as his fiancee, Tomu watches in confusion, commenting that his sister is making a bad joke and listens in as the person on the other line issues a challenge, saying they won't give up Takumi.
The next day, Tomu attempts to learn more about Takumi by asking him a series of questions but is unable to get him to speak. All he draws from the boy is a sarcastic remark that enrages Kaon. He, Kaon and Ichitarō Tomikōji are seen in a car as Tomu reminds Kaon that they must become friends with Takumi because of the favor to Tora which would be good for their family endeavor to build a kindergarten and elementary school on the campus. The trio arrive at their destination, Maid Latte, and are confused by the non-maid uniforms. As Kaon tells Ichitarō to speak without his machine, Tomu ask her to reconsider but is too late to stop the other boy as he begins running off in a rapid, redundant speech. Kaon punches him to stop the tirade and Tomu reminds her of their childhood suffering from this habit.
They formally ask to be served by Misaki and begin to ask her about Takumi’s personality because they “want be friends”, though there is clearly a mocking air to this discussion. Regardless, Misaki gracefully sidesteps their questions and recommends items from the menu. Tomu and Ichitarō willingly order drinks and he informs the angered Kaon that she should take this moment to improve her experience. He then remarks that such cheap living should only be done occasionally and that Takumi must be amazingly tolerant to put up with it; he suggests that it must be due to a lack of friends that he does this.
However, Takumi reveals himself dressed in cosplay and asks them not to make assumptions of his pleasures. The group is shocked by this outfit and question the dignity of cosplay. When Takumi’s retort insults Kaon’s prized bear, Tomu quiets her by placing earphones on her head to play the soundtrack of animated films. He asks Takumi if he is serious and is then challenged to a card game with him and Ichitarō against Takumi and Misaki. After watching the incredible speed of Misaki, Tomu remarks to have lost his fighting spirit while Ichitaro loses his card to Takumi. When he becomes upset, Tomu asks him if he likes card games that much.
Later, the trio leave the café with Tomu calmly remarking how they had been defeated. Ichitaro congratulates Kaon’s prowess of games and Tomu remarks that as the heirs of a toy industry, it was their duty to master every game. Ichitaro remarks that Kaon is more serious than Tomu and he admits to having no completive spirit. Both boys reflect on Kaon’s wild behavior after she joined the game, amazed that no one was injured as would usually happen. They suddenly receive a call from the vice president and depart. 
- His last name, Umekōji means "plum malt".
- His specialty is playing arcade games.
|Tora Igarashi • Kanade Maki|
|Hirofumi Koganei • Chiyo|
|Kaon Umekōji • Tomu Umekōji • Ichitarō Tomikōji • Tenryū Arashiyama • Yi Hua Li|
- Kaichou wa Maid-Sama! Manga: Chapter 65, Pages 19-20
- Kaichou wa Maid-Sama! Manga: Chapter 65, Pages 20-21
- Kaichou wa Maid-Sama! Manga: Chapter 65, Pages 21-22
- Kaichou wa Maid-Sama! Manga: Chapter 65, Page 25
- Kaichou wa Maid-Sama! Manga: Chapter 65, Pages 27-28
- Kaichou wa Maid-Sama! Manga: Chapter 66, Pages 1-2
- Kaichou wa Maid-Sama! Manga: Chapter 66, Pages 4-8
- Kaichou wa Maid-Sama! Manga: Chapter 66, Pages 10-15
- Kaichou wa Maid-Sama! Manga: Chapter 66, Pages 16-22
- Kaichou wa Maid-Sama! Manga: Chapter 66, Pages 24-26