Hachiman has been a loner since elementary school. Despite trying to fit in and get along with others around him, he was bullied psychologically for much of his life. There aren't any specific reasons why he was singled out, but Hachiman mentions several socially awkward things he was mocked for during the series. His bullying can be attributed to being naturally socially awkward, not playing sports, and an otaku lifestyle. Over the years Hachiman stopped trying to fit in and started avoiding others. At the end of middle school Hachiman successfully entered Sobu High School, a difficult school to get into and in another part of town, in order to avoid his middle school bullies and classmates and have a fresh start. Unfortunately Hachiman was involved in a car accident on the first day of high school causing him to miss the first month of school. This and Hachiman's already negative/loner mindset ensured he avoided everyone and remained a loner in high school.
Hachiman got his name because he was born on August 8th (8/8, Hachi means 8). Since his birthday occurs during summer vacation, he was never wished a happy birthday by his classmates.
He has never received any chocolate from the opposite gender during Valentine's Day, other than from his sister Komachi Hikigaya, even his own mother neglected to give him any chocolate.
Because Hachiman didn't have any friends, he would play baseball by himself. He would throw, hit, and catch the ball by himself. When he tried to devise a scheme to make the game last as long as possible, he realized that really high "pop flies" were the best way to lengthen the game.
He feared asking anyone about the content of an upcoming test, and instead just studied silently alone and then faced the consequences later. This left him with no chance of clarifying doubts or lessons leading to poor grades, especially in science and math.
Hachiman was invited to a birthday party because the whole class was obligated to go but was not invited a second time. Hachiman feels that he might have made some fatal social mistake to not be invited again.
Hachiman had a lot of acquaintances whom he thought to be his friends but they did not consider him to be one. He received corn as a birthday present from a classmate he thought was his friend. The corn was actually a gift from the boy's mother to Mrs. Hikigaya. Hachiman would ask to hang out with his acquaintances, all of whom would make excuses to not hang out. But when he ventured out on his own he would see his "friends" hanging out without him.
Elementary school is where Hachiman's loner lifestyle started. Hachiman was name called and compared to super strong and gross diseases. Girls did not like to be involved with him and found him creepy. He was often avoided and ignored, any attention he received was usually negative.One time Hachiman overheard a group of kids who were playing tag. They were talking about passing a virus named after him. The "Hikigerma" virus was so powerful that barriers (in tag) were ineffective. His classmates would also "forget" his name and give him insulting nicknames, "Hikikaeru (Hikifroggy)" (Hikkiribbit in the Sentai Translation, Hikiguana in the Yen Press LN). During the elementary school trip to Chiba Mura Park. Hachiman was able to get all of the answers for a trivia game correct but he was ignored by everyone in his group. He was paired with a girl for the final camp dance, but she didn't want to hold hands with him. In Hachiman words, he danced the "Air Oklahoma Mixer".
Hachiman began being excluded from school groups and group projects. He was hopeful that his homeroom teacher Isehara-sensei, would reprimand his classmates for their bullying. She didn't and Hachiman still hasn't forgiven her for not sticking up for him.
People used to stuff garbage in his shoe locker, the culprits would not even try to hide their criminal conduct which made it hurt him even more. Girls would falsely confess their feelings for him as a penalty for losing at rock-paper-scissors. He would also receive fake love letters written by boys who copy down what girls dictate to them. All of these things used to give Hachiman hope, but he now knows "an experienced loner never falls for the same trap twice".
Hachiman received a medal for his "A" score in the sports test during the closing ceremony. Everyone burst out laughing because this was just a prank by others filling out false athletic scores.
In order to not be bullied further he would agree to pass along class letters unaware there were insults about him written on them.
In middle school there was a friendly atmosphere between students and teachers, and everyone addressed each other by first name with the exception of Hachiman. Hachiman retained his loner attitude from elementary school. Partly because of his loner status Hachiman became the victim of verbal and psychological bullying in junior high.
Hachiman tried his best to be sociable during middle school life, but all attempts failed and he was ostracized. His actions were made out to be a joke for others, their opinion of him was creepy, gross, and uninteresting. After being ostracized he slowly became disinterested in social life.
Classes got reshuffled for second year and everyone exchanged numbers. Hachiman mustered enough courage and awkwardly asked a girl who reluctantly exchanged numbers. Hachiman used to text girls often (including Kaori Orimoto). According to Hachiman 40% of the replies he got were dismissive, 30% of the time he would get no reply, and the last 30% consisted of texts from some "foreigner" called MAILER-DAEMON (indicating a few girls gave him an invalid email). It wasn't until high school that he realized he would only get replies out of pity.
2nd YearWhen he was in the 2nd year of middle school, the role of class male representative was dumped on him by the fellow male students. While a girl volunteered to be the girls representative, that girl frequently talked to him. He thought she was interested in him. One day, he decided to ask her who she liked. She replied with the first letter which was "H". Hachiman asked if it was him. The girl was surprised and disgusted. The next day Hachiman saw a drawing mocking him on the class chalkboard, and to his shock and dismay the whole class know about it even though it was just the two of them at that time.
In a Drama CD, there was a girl he liked who belonged to the wind instrument club. On that girl's birthday, Hachiman gave her an anime music CD he made. He paid careful attention to the song selection. His present was accepted. But the next day at lunch time the broadcast committee played his CD over the school PA and mocked him. After this incident, the name Otagaya was passed on to his sister Komachi who pretended not to know who Hachiman was.
Near the end of second year, Hachiman had managed to get a few more phone numbers. Kaori Orimoto was one of the nice girls who would sometimes reply to Hachiman. He constantly texted her for silly reasons and eagerly waited for her reply. During Kaori's conversation with Haruno, she couldn't recall talking or texting Hachiman indicating it was a much bigger deal for Hachiman and Kaori was just being nice. Hachiman eventually confessed to Kaori, since she didn't recall talking to him she was surprised and turned him down. Despite the fact that the confession was private, everyone in class was gossiping about it the next day. The gossiping girls felt sorry for Kaori that Hachiman was the one to confess to her and were glad that they didn't give their contact IDs.
Kaori once mentioned that Hachiman wasn't in any clubs in middle school and was basically mute so he didn't stand out.
3rd YearThe last time he talked to a girl was nearly two years before he met Yukino, In June of his final year of middle school. He mistakenly responded to a girl who was complaining about the heat. It turned out that she was actually talking to another girl seated behind him. What followed was an awkward situation. Whenever Hachiman recalls this memory, he hides and screams to himself under his futon.
After middle school, Hachiman didn't want to have anymore contact with his middle school classmates, which he calls a "Reset" or "Deletion" in his relationships. Because of this, he worked hard to enter Sobu High School, where his middle school classmates would definitely not go to. Only one person from Hachiman's middle school gets into to Sobu High each year because of its high academic standards.It was mentioned he used to cosplay. He was an otaku to some degree and often makes references to different animes and mangas during his inner thoughts. He mentions he stopped most of his otaku behaviour at some point in high school.
He goes to school by bike, despite the long distance and intense weather. The main reason is to avoid running into old classmates and acquaintances of his on the subway.
On the first day of High school, he was very excited about starting his new student life, to the point where he headed to school an hour early. On the way to school he spotted and saved Yui's dog Sable from a potentially fatal car crash
The result of the accident was a bone fracture that caused him to be bedridden in the hospital for three weeks. Hachiman thinks this put him on the fast track to his loner lifestyle, since everyone else had become acquainted and grouped up by the time he arrived. Yui went to his home to thank him but he hid from her, indicating his loner lifestyle would not change anyway.
Having missed out on a fresh start, Hachiman completely gave up on social life and continued his loner lifestyle. He would find an associate in Yoshiteru Zaimokuza, another outcast. Occasionally they would be the last two left together during gym class and ended up being paired together. They both agree they are not friends and merely acquaintances.
It was also mentioned that he had a lot of part-time jobs before joining the Service Club but none lasted longer than 3 days.
At lunch, Hachiman would eat alone at his favorite spot because of the nice sea breezes that blow in from the shore, and also to be away from class pressures. Almost all of the girls in Sobu High School treat Hachiman as someone that is gross and disgusting.
In his second year of high school, he was forced to join the Service Club by Shizuka Hiratsuka, in the hopes of fixing his rotten personality. While there he meets Yukino Yukinoshita and Yui Yuigahama who eventually befriend him.
Unknown to Hachiman, they were the other students involved in the car accident on the first day of school. He learns that the dog he saved belonged to Yui, and Yukino was in the car that hit Hachiman. Once he realized they were connected to this event, he slowly distanced himself from them for not telling him this knowledge despite their attempts to explain themselves. In the end, he would reconcile with them after realizing nobody was really at fault.
For most of the requests the Service Club gets, his solutions involve making him a villain or scapegoat. He doesn't mind getting himself hurt as long as it achieves the goal. Later on, he slowly starts to realize that his actions can hurt his new associates too and admits he hates the way he does things.
He slowly becomes better at interacting with other people and accumulates other peoples e-mail and phone contacts throughout the series.
He chose Liberal arts as his third year course.