as he was named offensive coordinator and quarterbacks coach at UNT. Despite being named OC at North Texas, Harrell said he would honor his contract with Leach and WSU and coach the Cougars in the Sun Bowl. At UNT, Harrell inherited an offense that had ranked in the bottom 25 of the country in passing, total yards, and points in 2015. He improved the unit such that his offenses were ranked in the top 26 nationally in passing, total yards, and points in both 2017 and 2018. USC On December 7, 2018, UNC-Chapel Hill sports site Inside Carolina claimed that Harrell had accepted the role of offensive coordinator at the University of Carolina–Chapel Hill, but Inside Carolina retracted the claim hours later. On January 29, 2019, Harrell was hired as the offensive coordinator and quarterbacks coach at the University of Southern California (USC) under head coach Clay Helton. West Virginia On January 10, 2022, Harrell was hired as the offensive coordinator and quarterbacks coach at West Virginia University. Purdue On December 20, 2022, Harrell was named the offensive coordinator for the Purdue Boilermakers. Personal life Harrell is the son of Sam and Kathy Harrell. His grandfather served as assistant coach to Gordon Wood. Harrell has an older brother, Zac, who was a receiver on Ennis High's 2000 State Championship team, and is a graduate of the University of North Texas and coaches at the high school level and is the head football coach and athletic director at Athens High School in Athens, Texas. Graham also has a younger brother, Clark Harrell, who played a year at quarterback for the Tulsa Golden Hurricane. Clark transferred to Abilene Christian University after his freshman season at Tulsa and graduated from ACU in 2011. Clark is now the head coach at New Diana High School in Diana, Texas. Sam Harrell, Graham's father, was the highest paid high school coach in Texas as of the 2005–06 academic year. He coached at Reagan County (1990–1993) and Ennis (1994–2009) before retiring from coaching duties in December 2010 due to health problems. Sam returned to the sidelines after over two years of aggressive treatment for multiple sclerosis and coaches in Brownwood under Bob Shipley, father of Jacksonville Jaguars and former Texas wideout Jordan Shipley. After a short stint as the offensive coordinator for the Southwestern Assembly of God University Lions in Waxahachie, Texas, Sam returned to Ennis High