Thomas was born in Chicago, Illinois, on August 26, 1995. Thomas and his family moved to Sydney, Australia when he was two years old, where he lived for five years. He attended Coppell High School in Coppell, Texas. He had 78 tackles and 12.5 sacks as a senior and 89 tackles with 8.5 sacks as a junior. He was rated as a four-star recruit and was ranked among the top players in his class. He committed to Stanford University to play college football.
