I'm going to have all five of you graduate with smiles on your face!
|― Fuutarou Uesugi|
Fuutarou Uesugi (
Fuutarou had an experience to get his ear pierced before. 
AppearanceFuutarou is a stern-looking young man with a short hair and tall build. He has a natural black hair color with a slight pigeon-blue shade on it. In his younger days, he dyed his hair blonde and have delinquent persona. Fuutarou is mostly seen in his uniform, even during summer festival and hanging out outside.
His Kintarou persona sports a blonde, more spiky, and slightly longer hairstyle.
According to Isanari, Fuutarou used to be similar to his father as a kid, with their wild personality and being bad at studying. Fuutarou lives a frugal lifestyle. He also has a calculative mind. Fuutarou prefers solitude, his friends remark that Fuutarou is "by himself again". Ichika remarks that Fuutarou is direct and doesn't mince words.  Yotsuba's first impression of Fuutarou is a gloomy and not-having-many-friends guy. His facial expression is always serious, sometimes having grumpy and annoyed look, and rarely blush or flustered.
Fuutarou is noted to have a big ego and high confidence. He can also be rude and straightforward, but is actually capable to hold back his emotions. Despite that, Fuutarou could momentarily lost his composure when agitated and faced with unfavorable circumstances. He also doesn't like getting involved with other people's problems, finding them to be troublesome.
Fuutarou is shown to be hardworking and has a high patience, as he is able to tutor several girls that have below average scores. It is personally stated and hinted that Fuutarou currently doesn't have interest in romantic relationships. He considers love as something foolish and detests it. 
Fuutarou tried to make Kintarou as someone more manly and brawny than the silent Fuutarou.
Fuutarou is a smart student and ranked top among his peer. He is able to score perfectly in various tests . Fuutarou gets 100 in all 5 subjects during the Second Year Midterm Exam. He also has an exceptional memory & excellent reading comprehension. Fuutarou is able to absorbs several dozens worth of book in three days.  Fuutarou's reason to study is related to a young girl in his flashback.  Fuutarou is able to sleep while sitting straight with his eyes wide open.  Ichika's director notes that Fuutarou is the one who draws out Ichika's potential.  Fuutarou is shown to have a cunning and crafty mind, as he's able to get the most out of the cafe's menu, successfully trick a teacher with his plan, and getting the lazy Nakano Quintuplets to start studying.
Fuutarou acknowledges that human relations isn't his strong point.  Fuutarou is less adept with technology, he is unfamiliar with the internet's function.  Another indication of Fuutarou's lack of knowledge in technology: he is unfamiliar with Nakano Quintuplets' apartment lock system.  Fuutarou has low physical endurance/stamina.  Miku and Fuutarou have almost equal physical endurance/stamina.  Fuutarou tried to piggyback Miku, but has no strength to do so.
Despite his poor social skills, he is able to see through a person's emotion and motivate them. Initially, Fuutarou is unable to judge the names of the sisters since they're so similar, but later he is able to differentiate them by how they call him.. He is also capable of distinguishing the girls' based on their individual style of writing.
Fuutarou's type of girl is "full of energy", "good at cooking", and "cares about her brother" (he's actually referring to Raiha). 
Fuutarou is shown to be in a good relationship with his father, as they joke around with each other casually.
Fuutarou is protective towards his little sister, rushing to her side when she's sick and willingly abandon his long-awaited school trip to take care of her. He also try to fulfill her wishes to make her happy.
Fuutarou refers to the day he met the Nakano Quintuplets as a nightmare.  Fuutarou's goal is to make the sisters graduate without problems. Fuutarou has a book called "The Quintuplets Graduation Plan", one of the content is the detail of Nakano Quintuplets' mock test results.  Early on the series, Fuutarou comments that dealing with all five sisters is hard. 
Ichika calls Fuutarou "Fuutarou-kun".  Ichika's first impression of Fuutarou is that "he's a bookworm who doesn't have a girlfriend".  Fuutarou's first impressions of Ichika is that she has eyes that seem to see right through you.
Ichika likes to tease Fuutarou, but he rarely flustered about it. Ichika initially had a pessimistic view towards the sisters capability to study, making her reluctant to be tutored by him. Her attitude lasted for quite some time until he helps Ichika to overcome her problems and made her closer to the sisters. She eventually began to study with him and the sisters.
Nino labels Fuutarou as "dull-looking guy".  Yotsuba notices that Nino doesn't directly kick Fuutarou out of the house after the midterm exam.  Nino is antagonistic and openly rebels against Fuutarou since their first meeting. She is seen boycotting Fuutarou's attempt to tutor the quints in several occasions. Fuutarou notices that Nino is someone who "scheme". 
Over time, due to Fuutarou noticing Nino's other side as a caring sister, she began to accept him. After knowing her sisters' acceptance to Fuutarou, she defends Fuutarou against her father. Nino is the only sister who rarely calls Fuutarou by his first or last name, using "you", "that guy", or other third-person nicknames. Despite the harsh treatment he gets from her, Fuutarou cares her just as much as the others and is always ready to help her when she's in trouble, even willing to "call" Kintaro, knowing that Nino wanted to see him.
Miku initially rejects Fuutarou as a tutor because she's expecting someone better. After Fuutarou found out her secret and appreciate it, Miku began to accept him, only to reject him again due to Fuutarou's lack of knowledge. He spent a lot of effort in convincing her again, and successfully get her approval. Fuutarou also motivate and inspire Miku to start studying, making her to be the first sister who accepts Fuutarou as a tutor.
Yotsuba calls Fuutarou "Uesugi-san". 
Yotsuba is the only sister who accepts Fuutarou as a tutor early on in the series. She happily cooperates with him to help make her sisters accept him as a tutor.
Itsuki had a quarrel with Fuutarou, leading her to rejects him as the sisters' tutor early on. Due to Fuutarou's consistent efforts, Itsuki began to notice the change on her and the sisters. Itsuki usually compares her father to Fuutarou due to her mother's words. She and Fuutarou develop each other's character, as they both overcome their stubbornness. During the Scrambled Eggs Arc, Itsuki is revealed to feel that their relationship is no longer that of partners, but to that of friends.
- "I shall help all of your daughters successfully graduate!" - Fuutarou Uesugi
- "Love? That is the stupidest, furthest removed act from academics. Anyone who wishes to engage in romance may do so. But, their life will peak when they are a student" - Fuutarou Uesugi
- "It's not weird! Trust in what you like!" - Fuutarou Uesugi
- "I will teach her even if it kills me!" - Fuutarou Uesugi
- "I'm gonna make sure all five of you graduate with a smile" - Fuutarou Uesugi 
- "If one of you can do something.. all of you can do it. Ichika, Nino, Yotsuba, Itsuki, and you too, Miku. I believe the potential to score 100 points rests within all five of you!" - Fuutarou Uesugi
- "I shall help all of your daughters successfully graduate!" - Fuutarou Uesugi
"Love? That is the stupidest, furthest removed act from academics. Anyone who wishes to engage in romance may do so. But, their life will peak when they are a student" - Fuutarou Uesugi "It's not weird! Trust in what you like!" - Fuutarou Uesugi "If one of you can do something.. all of you can do it. Ichika, Nino, Yotsuba, Itsuki, and you too, Miku. I believe the potential to score 100 points rests within all five of you!" - Fuutarou Uesugi "I'm gonna make sure all five of you graduate with a smile" - Fuutarou Uesugi 
- "I want to make all her wish come true" - Fuutarou Uesugi
- He is an Aries and believes in charms and horoscope.
- Nino is the first Nakano Quintuplets to be pushed down (although accidentally) by Fuutarou.
- Nino is the first Nakano Quintuplets who is seen half-naked by Fuutarou.
- Fuutarou's favorite meal is curry udon.