Lessons in Love primarily revolves around the Main Cast.
The original main cast consists of 10 characters beside Sensei: Ami Arakawa, Ayane Amamiya, Chika Chosokabe, Futaba Fukuyama, Makoto Miyamura, Maya Makinami, Miku Maruyama, Rin Rokuhara, Sana Sakakibara and Yumi Yamaguchi.
The patron release of Version 0.7.0 on September 1st of 2020 added two new Main Cast characters, Molly MacCormack and Tsuneyo Tojo. They marked the first addition to the original cast, totalling their number to 12 beside Sensei. Unlocking them requires a certain progress in the Main Story.
As the total pledge reached $5000 on the 18th October 2020, Selebus announced an addition of 8 characters joining the main cast. They were added across four different releases:
- Version 0.12.0p2 added Io Ichimonji and Uta Ushibori.
- Version 0.14.0 added Noriko Nakayama and made Kirin Kanda a main character (she had previously been a part of the Side Cast).
- Version 0.15.0p2 added Nodoka Nagasawa and Otoha Okakura.
- Version 0.16.0p2 added Touka Tsukioka and Yasu Yasui.
Just like Molly and Tsuneyo, it is required to progress the Main Story to unlock them.
- Over the course of the first Chapter, there have been key-events showing the new characters off in the background. They are hard to spot initially.
- Shrek, the main character from DreamWorks Animation's Shrek franchise, was jokingly announced as the twenty-first Main Cast member by Selebus.