Age: 13-15; 23-25
Date of birth: September 9
Height: 168.5 cm
Nationality: Japanese/Italian
Known relatives: Bianchi (Half-Sister), mother (deceased), father
School: Namimori Junior High
Grade: 1st year, 2nd year (later in the series)
Rings: Vongola Ring of Storm, 4 Rings from Sistema C.A.I.
Box Weapon: Leopardo di Tempesta ver. Vongola (Uri)

Gokudera was born in Italy and is 3/4 Italian and 1/4 (mother) Japanese. His blood type is B, is 168 cm tall, weighs 54kg and his hair is silver. His future dream is to become the Tsuna's right-hand man. He has an ability to play the piano. He dislikes people that are older than him, Bianchi and Lambo. Gokudera is also a chain smoker, but they remove this in the anime adaptation.

At school, Hayato is adored by many of the female classmates who view him as the "rebellious badboy." During Valentine's Day, a large group of females constantly followed him around trying to give him chocolate, although Hayato seemed to be more annoyed than flattered by this. Despite his image of a rebel, Hayato excels in his schoolwork and aces all his tests, much to the surprise of Tsuna. This is probably due to his rich upbringing, suggesting that he probably had a multitude of private tutors when he was young. He idolizes Tsuna greatly and considers himself to be Tsuna's right-hand man.

Due to a traumatic childhood experience, every time he sees the face of his older sister, Bianchi, he becomes sick, sometimes even falling unconscious. Oddly enough, he is immune to his sister when she happens to be wearing something that covers part of her face (i.e. glasses or goggles).