The butler of the Sanzen'in family, Hayate Ayasaki has had to work to support his parents' bad habits since the age of nine, always moving from job to job by the time he is found out to be underage. The experience gained does mean, however, that he of all characters possesses the most extensive practical knowledge as to how the world operates. Hayate's dad has refused to get employed, while his mother is a compulsive gambler, and the whereabouts of Hayate's older brother, who is not named, are unknown. These events led to their bankruptcy—they abandon Hayate after selling his organs to the Yakuza to ease their financial burdens. With not many choices left to him, Hayate conspired to kidnap someone to get ransom money. He found a girl, Sanzen'in Nagi, and told her that he would kidnap her. However, Nagi mistook his words for his confession of love, so later he was employed as Nagi's new butler. In the beginning of the story he often mentioned Nello and Patrasche from the novel A Dog of Flanders and compared his miserable situation to the characters' life.
Characters in the series are always remarking that he looks poor and seedy (for example, Yukiji does so when Hayate tries to enter Nagi's school in Volume 4 of the manga or Episode 4 of the anime), and he has terrible luck. He has experienced so much hardship through the terrible life with his parents that he tends to think that he is disliked by everyone around him except children, although he doesn't think about children being anything other than friends, including Nagi - he genuinely does want to impress Nagi for giving him this new job. Hayate doesn't notice Nagi's feelings about him, but he often say things which please her without intention, and as a result Nagi thinks that Hayate loves her, keeping the misunderstanding running. As a butler, Hayate is capable of all aspects of housework and can even play the violin, but it is his ability in repelling attacks from almost anything, including butlers of other families (despite his bad luck) that makes him a "combat butler." He once demonstrated a skilled use of fire-arms (capable of wielding a HK MG3 single-handed) and is essentially invincible with physical prowess far surpassing any normal human being (Hayate once parried a sword thrust easily with just two fingers and in Volume 8 revealed that doing over 350 one-finger push-ups is part of his daily routine since he was little, among other displays of his strength). At the end of volume six, Hayate manages to create an ultimate technique called Hayate no Gotoku (Like the wind). Hayate sees Nagi as a child, but has a crush on the more mature Maria. In chapter 156 it is revealed that he sleeps three hours a day: studying until 2am, waking up at 5am (the reason he gets up at 5 is that he thinks it would be unwise to wake up after Maria has done so).
In addition to looking poor and seedy, Hayate can also appear to be extremely feminine. He has a girlish face and is good at housework such as cooking and cleaning, which are usually thought to be work for women; he is also very modest and sensitive, all of which contribute to others' perception of him as feminine. This has led to him being forced to wear girls' clothing or cosplay in feminine outfits such as nekomimi, a maid and so on. In episode 36 of the anime, he cosplays as Belldandy from Ah My Goddess. Both Tama and Klaus have fallen for Hayate when he wears girls' clothing. Later on, this female alter-ego is given a name: Ayasaki Hermione (綾崎 ãƒãƒ¼ãƒžã‚¤ã‚ªãƒ‹ãƒ¼,Ayasaki Hamaioni?), which is probably a reference to the main heroine of the Harry Potter series. Ayasaki Hermione has officially "appeared" once in each season of the anime (officially meaning whenever Hayate lies by saying his name is Ayasaki Hermione in order to hide the fact he was unintentionally cross-dressing at that time. He has been forced to cross-dress at other times, but he is not referred to by his alter-ego's name on these occasions). However, in recent Hayate no Gotoku manga popularity polls, it was seen that there are votes for two different characters, one being Ayasaki Hermione (綾崎 ãƒãƒ¼ãƒžã‚¤ã‚ªãƒ‹ãƒ¼,Ayasaki HÄmaioni?), the other being Hayate dressed as female (女装ãƒãƒ¤ãƒ†?).
Although he possesses a wide range of skills, his empathy is very poor, to the point where he often hurts the people around him because he doesn't understand their feelings towards him. On the other hand, he often unintentionally embarrasses others by reacting wildly at very simple requests (such as in volume 8, when Hinagiku asks if he wants to take a bath and he thinks that she wants to take a bath together). This may be because of his innocent personality, which often leads him into trouble with other people. While he does not believe that Hinagiku likes him, in volume 8, when the two of them are alone in her house shortly after Hinagiku has finished taking a shower and the scent of her shampoo is in the air, he thinks to himself that he had always thought that Hinagiku was a very beautiful girl. And as Hinagiku often helps him out on more than one occasion, he ends up making biscuits for her on her birthday and on White Day.
He had a girlfriend named Athena, who was responsible for teaching him cleaning and swordsmanship, as well as for building his strong body. They had a falling out after his parents pawned an "engagement" ring she gave him. In chapter 239 after being asked by Hinagiku how he feels about Athena, Hayate describes Athena as "Not like the others," and ultimately tells Hinagiku that he is in love with Athena. Following her advice to meet her, he goes to her mansion and confronts Machina, who nearly kills him and steals his King's stone before Athena brings him in and treats him.
