In 1926-30, Rupp accepted the basketball head coaching position at Freeport High School, (Freeport, Illinois) where he also taught history and economics. During his four years at Freeport, Rupp compiled a record of 66-21 and guided his team to a third-place finish in the 1929 state tournament.[4] While at Freeport High School Rupp started William "Mose" Mosely, the first African-American to play basketball at Freeport and the second to graduate from the school.[5]