Jeremiah Sio is from South Seattle and played football as a safety and running back for Rainier Beach High School. He began playing rugby in high school for the Eastside Lions of Rugby Washington and was selected multiple years for the Washington Loggers. He played for the Eagle Impact Rugby Academy Under-19s Boys Elite 7s side in 2017 at the Emirates Dubai 7s, the Atavus All-Stars, and EVO 7s Idaho at the North American Invitational 7s Championship in 2018.
Following his high school graduation in 2018, he played club rugby with Seattle Rugby Club. He attended the Seawolves’ first talent identification camp in July 2021 and his performance earned him an invitation to attend preseason in November by head coach Allen Clarke. He continued to train with the Seawolves in 2022 and played against Seattle RFC in a Seawolves preseason match.