Mr. Ōgi is a former teacher whom Miyabi Aizawa had a crush on and who met Eikichi Onizuka at some point and revealed his past to him.
Miyabi had crush on Ōgi, but he revealed that he was engaged with another woman named Maho Sumida and he mentioned that "We're getting married... next spring."; which caused Miyabi's jealousy. She decided to take photos of herself to send him and she lied to the class that she was raped by Ōgi, which provoked Takumi Ishida to beat him in front of everyone and the school to fire Ōgi and expel Takumi.
In Chapter 188, Ōgi reveals to Onizuka that "I even lost my fiancee over this whole thing.", implying that Ōgi and Maho has ended their engagement after he was falsely accused of sexually harassing Miyabi.