Cox joined the Federal Highway Administration in 1977 from Madisonville, Kentucky, where he was the senior vice president of Ligon Specialized Hauler Inc.[4] He was one of the youngest persons ever elected to the Kentucky legislature, but did not seek re-election after being one of a minority of Democrats who supported Republican Gov.

He was a special assistant to Carroll for legislative relations, then vice chairman of the Kentucky Public Service Commission.

He was noted for his untiring efforts to streamline administrative processes by eliminating or minimizing excessive regulations and "red tape."

[5] The controversy created an opening for Martha Layne Collins, clerk of the state Court of Appeals, who won the primary with 109,031 votes.

On November 19, 2017, Bill Cox died peacefully surrounded by his immediate family at 5:11 a.m. Eastern Time on Sunday at Baptist Health Hospital in Louisville, Kentucky.