In his remaining time as an undergraduate, Biles served as an assistant with the squad, then officially began his coaching tenure at the high school level.
In 1953, he served as an assistant coach at Woodward High School in Cincinnati, while also finishing work on his master's degree.
Biles would remain in that position for the next six years, with a record of 20–4 until he was promoted to head coach of the varsity on November 24, 1961, following the departure of Edward Doherty.
When Gillman retired at the end of that season, he promoted Bum Phillips to head coach, with Biles becoming the team's defensive coordinator.
Biles inherited an aging football team and was unable to maintain the winning ways, falling to 7–9 in 1981 before dropping to 1–8 in the strike-shortened 1982 NFL season.
In 2005, he was hired as head coach of the Cincinnati Marshalls of the National Indoor Football League, but resigned on May 31 when additional duties were given due to the team's shaky financial condition.