Leo, a native Washingtonian, received his Bachelors and Masters degrees from Virginia State University.
After attending VSU, Miles played professional football with the New York Giants. A leg injury caused him to terminate his career as a professional athlete, but Leo continued to coach football and teach in the DC Public School System. His career was spent primarily at Bell Vocational High School and Lincoln, Jr. High School, where he won four divisional and three city football championships.
Motivated to serve, Leo continued his career at Howard University as Director of Athletics for 17 years. Miles was credited with helping elevate the school's athletic program via the achievement of NCAA Division I status in 15 varsity sports. Prior to being hired by the NFL in 1969, Miles, who began officiating sports when he was 15, served 12 years as an official with the CIAA. In 1974, he was the first African-American to officiate a Super Bowl Game. Upon retiring from Howard University, Leo continued as an official for 22 years as head linesman, then culminated his career as a Supervisor of Officials in the New York City Main NFL Office.
In 1995, Miles' passing was chronicled in Jet Magazine with the headline, "First Black Super Bowl Official Dies in VA." Leo is enshrined in the Halls of Fame of Virginia State University, the Mid-Eastern Athletic Conference, the Eastern Board of Officials and the National Association of Collegiate Directors of Athletics.