Cullen Mills was born and raised in Killeen, Texas. He attended Harker Heights Elementary, Eastern Hills Middle School, Killeen High School, and graduated in 2002 from Harker Heights High School in Killeen ISD. He earned a scholarship to play football at the University of North Texas, where he earned a degree in Economics and met his wife, Erin Mills. After graduation, Cullen and Erin planted roots back in Killeen to raise their two children, Noah, and Avery Anne.
He has served his community in several capacities, including the Executive Board of Killeen ISD Education Foundation, the Killeen Housing Authority Board, the Board of Governors for the Fort Hood Chapter of the Association of the United States Army, the Killeen ISD Bond Steering Committee in 2018, and the Fellowship of Christian Athletes Heart of Texas West Board. Cullen and his family are members of the First Baptist Church of Killeen where he and Erin teach Sunday School for 9th and 10th-grade students.
Cullen is the proud owner of his family’s small business, Modern Appliance, which was founded and built by his grandfather, TJ Mills, in 1957. He is a third-generation School Board Trustee, following in the footsteps of his grandfather, TJ, and father, Billy Mills.