A Sanger High graduate and former athlete at Fresno State, Darby coached track and cross country at Wasco High for 39 years. He led the Tigers to a 201-41 record in track dual meets with 75 straight meets without a loss at one point. His teams won 13 South Sequoia League championships and one Central Section title. In cross country, Wasco won several SSL titles, the Central Section small schools titles from 1959-61 and another section title in 1975. Darby and Delano coach Don Tavolucci organized the South Valley League in 1954, the first organized cross country league for Kem County teams. As an athlete, Darby played football and competed in track. He ranked sixth in the U.S. in the javelin in the early 1950s with a lifetime best of 221-9. Darby was also an official at several high-level track meets including the 1952 West Coast Relays, the 1967 AAU Championships and the 1969 All-American Games.