Tsukasa Domyoji (道明寺 司,Dōmyōji Tsukasa) was the de facto leader of the F4 and the heir of Domyoji Group. His best friends were Rui Hanazawa, Sojiro Nishikado, and Akira Mimasaka, whom he had known since their childhoods. In high school, Tsukasa met Tsukushi Makino, one of the few people to stand up to him. After several trials and tribulations, they became a couple and were engaged.
Tsukasa was born on January 31 into the Domyoji family as the future heir of the mega conglomerate, Domyoji Group. His immediate family consisted of his mother, Kaede, father, and older sister, Tsubaki.
After middle school, Tsukasa went on to Eitoku Senior High with his friends, now called the F4. At some point, they took control over the school and only wore street clothes. They also began handing out red cards, their "declaration of war", to those who defied the F4, including Kimoto. The red card was a signal for the other students to start bullying the individual.
Tsukasa: "You don't mean that! Just who do you think you are, pauper?! I'm name-brand from head to toe! What about you?"
Tsukushi: "I'm no name brand. I'm just me. That's all"
Tsukasa first met Tsukushi Makino, a poor student at Eitoku, after her friend fell down the stairs and landed on him. He refused to forgive her and threatened to give her a red card. Tsukushi defended her and insulted the F4 by saying "you [have] never had to work for anything you [have] got." In response, they gave her a red card the next day. Tsukushi defied them by deciding to fight and declaring her own war on the F4. At first, he allowed the other students to bully her, hoping this would drive her away. Tsukasa quickly became determined to force Tsukushi out of the school. He was also offended when Sojiro and Akira compared her to Tsubaki. His next move was to hire four Eitoku students to assault Tsukushi.
The attempted assault failed as Rui protected Tsukushi. The next day, Tsukasa was kicked by Tsukushi in retaliation. Before passing out, Tsukasa mumbled something about his sister. Tsukushi's popularity among her classmates grew after this incident. Tsukasa was brought out of his state of shock by this revelation. He then decided to have her kidnapped. He brought her to his mansion, where she was given a makeover at his home salon. Tsukasa clumsily offered to allow Tsukushi to hang out with him, though only when no one else was around. She rejected by saying "I [am] not for sale". Despite being spurned, Tsukasa was still attracted to Tsukushi. He soon became convinced that Tsukushi was in love with him, especially she said "I [am] still a virgin." However, her saying this was actually a misunderstanding.
Tsukasa's most notable trait was his extremely curly hair. His hair could be straightened for brief periods of time, though it would curl again in the blink of an eye. Despite his odd hairstyle, Tsukasa was still considered good-looking by his peers. F4, shortened from Flower 4, was a reference to his and his friends handsome faces.
He is voiced by Takumi Nishio, the first person to portray Tsukasa, in three drama CDs. Yoko Kamio was happy with his performance and felt "he caught that slightly dopey drawl of Tsukasa's". Upon telling Nishio and Takuya Kimura (Rui's part) that they fit the character's images, Kimura jokingly told Nishio that Kamio said he was as stupid as Tsukasa.
Jerry Yan portrays Dao Ming Si, a version of Tsukasa, in Meteor Garden (2001). Si falls in love with Shan Cai (Tsukushi) and pursues a relationship with her, despite many hurdles. Yan's portrayal closely follows the original manga, mirroring Tsukasa's personality and actions.