Bill Farrell was a standout football player at Jacksonville High School before graduating in 1943. He played football at Jacksonville State and served as captain of the then Eagle Owls football team in 1946 before graduating in the spring of 1947.

Farrell landed his first coaching job at Ohatchee high school in 1947. He took on the task of building a football program with a school that had not fielded a football team in eight years. His very first team finished with an 0-7-2. In 1951, Ohatchee went 8-0-2 and were Calhoun County champions. It was the first undefeated team in school history. He was named Calhoun County coach of the year.

Coach Farrell accepted the head coach position at Piedmont in 1952. The Piedmont Bulldogs finished with winning records in seven of his eight seasons with the program. His eight teams went 54-20-1 overall.

His final two Piedmont teams were 9-1-0. The 1958 Bulldogs defeated Wellborn 26-6 in the Turkey Bowl to avenge their only regular season loss.

Farrell stepped down after the 1959 season and spent the next ten years as a principal – two years at Lineville, one in Georgia, then seven years at Ohatchee. He was vocational guidance director for the Calhoun County school system during the 1970-71 school year.

In 1971, Coach Farrell took over the football program at Anniston. It was another rebuilding job as the Bulldogs had managed only one winning season in the previous seven seasons.

Farrell was Big Six coach of the year again in 1973 and 1974, sharing the award with Jack Stewart in 1974. In 1973 he was also voted North East Alabama Conference coach of the year. The 1973 team was the first at Anniston to complete a regular season schedule undefeated and untied. It was also the first to reach the state playoffs.

He resigned after the 1978 season then returned in 1986 for one last campaign. When he retired midway through the 1987 season his overall career record was 133-67- 7. Farrell was inducted into the Alabama High School Sports Hall of Fame in 1999.