Makoto usually gets along well with his older brother, with whom she lives on the same flat. However, it is not uncommon for them to have their discrepancies because of their opposing personalities. Makoto is much more cavalier about challenging the rules, while Naomasa is very much adheres to follow the laws and proper procedures.
Naomasa knows that her sister knows the Naruhata Vigilantes, who have participated in acts of vigilantism in addition to using their Quirks without being heroes, which is illegal even though they do not seek to cause problems, but Makoto protects them and doesn't want them to be treated as criminals.
It's also a common source of friction is when she asks him about any villains or hero information he has learned of, to which he replies that he cannot leak any confidential information, especially regarding All Might.
Makoto meets Koichi in their university, when she offers to help him in his studies. Of course, this help was accompanied with the ulterior motive to use him as help for her thesis about Vigilantism, in addition that she suspects that he is The Crawler, one of the Naruhata Vigilantes. However, she makes the mistake of asking him if he was the Cruller, which does not set off her Polygraph quirk when he denies it.
Both become friends, but Koichi also has a small crush towards Makoto, feeling jealous when another man showed interest in her. Makoto, on the other hand, only saw him as a friend at first, however it is implied that she starts to fall for Koichi after finding out he is the Crawler while being rescued during the Monster Cat incident.
Makoto has a good relationship with Kazuho. At first, she did not seem to be aware that Kazuho did not have a good opinion of her because of the jealousy she felt because of Koichi's interest in her, but after Makoto helps her to overcome her stage fears and boost her career as an idol, makes her opinion changes for the better, and their relationship improves a lot.
Likewise, Makoto knows of her secret identity as Pop Step and her acts of vigilantism, but she promises to Kazuho that she would not mention her masked escapade to anyone.
At first, Makoto Tsukauchi was part of Christopher Skyline’s cheerleading group, and due to his womanizer attitude, he invited her to a date to flirt with her, but when Makoto told him that she became friends with his ex-wife, and she is in contact with her, all attempts to seduce her abandoned him.
From that moment, Makoto went from one of the Captain Celebrity cheerleaders to her boss and now he is completely terrified of her. Makoto gives him a very busy schedule and does her best to change his attitude and behavior and improve his public image.
Although he still feels a little scared towards her, Christopher appreciates everything she did for him, and considers Makoto a good friend.
Makoto meets Koichi's mother when she goes to visit his penthouse. Due to a series of lies from Koichi, he asks Makoto to pose as his girlfriend, but Shoko realizes at once that everything is a farce. In spite of this, she does not get angry with Makoto if she does not consider her a lovely and pleasant girl, and therefore, completely out of Koichi's league. While they tour the city, Shoko even comments on how she would prefer having Makoto around instead of her son.
Shoko considers Makoto to be the ideal daughter-in-law and tells hers to join the family, in which she states she’ll give thoughtful consideration.
Makoto became friends with Pamela, Christopher’s wife, on the internet. Pamela doesn't want him going back to his old ways, so Makoto is responsible for keeping the playboy behavior of Christopher at bay, threatening to communicate to his wife when he does what he should not, risking another lawsuit from her.
They are both good friends, and they often call each other frequently. Makoto acts as a confidant of Pamela, who tells important things to her before Christopher, as she did when she was pregnant with his son, something that Christopher completely ignored for months.