Dieter was born in the US and spent most of his childhood in Germany but he also stayed in the US. Dieter moved to Asia with his family because of his father's job as an officer for the US Navy. Growing up, he never really had a permanent home so he often struggles to properly explain where he comes from. 

His father was an immigrant and joined the US Navy after he was naturalized and his mother was a German tourist visiting the US. His parents met during his mother's visit, and they decided to keep in touch and visit each other a few times a year. Eventually, they got married and Leah was born, and then, Dieter.

Dieter met Yeong-Gi and Soushi the summer before their first year in high school.

Dieter is a judoka, or someone who practices judo, a Japanese form of wrestling. Dieter was invited to the school Tae Kwon Do team by Min-Hyuk Park, the captain of the team at the time, but Dieter declined due to the two sports being vastly different. 

Throughout his friendship with Min-Hyuk, he managed to ask him about Shin-Ae many times, before Min-Hyuk left for Chicago.

Dieter had a crush on Shin-Ae for quite a while before he decided to confess to her.