Gardner Gilliland played football at Cleveland High School and was a 1988 graduate of the school. He attended and graduated from Auburn University.

As head coach at Oneonta from 2005 to 2009, Gilliland was 40-18 overall and 4-4 in the playoffs. He was the defensive coordinator for the Redskins state championship team in 2004. His 2005 team at Oneonta finished 12-1 and won the region title.

Gilliland was an assistant at Boaz High School for two seasons before returning home to Cleveland and accepting the head coach job at the school in 2013.

His nine seasons with the Panthers produced a record of 71-36 and 9-8 in the playoffs. His 2015 team won a region championship with a 10-0 regular season record before falling in the third round of the playoffs to Randolph County 49-28.

In fourteen seasons as a head football coach his record stands at 111-54 with a dozen playoff appearances.