 At age 28, he became head coach at 2A Hamlin High School, where he coached from 1984 to 1985.He guided the team to a 27–1–1 record including a 35–19 loss to Electra High School in the 1985 state semifinals.His instant success caught the attention of bigger schools, so Briles left Hamlin for 5A Georgetown High School in 1986, where he had a difficult two-year span in the school's first two seasons at the highest classification in Texas high school football at the time.