He is the son of John and Danielle Jaeschke. Thomas has a twin sister named Jaime and a brother named Joseph. Jaeschke went to Wheaton-Warrenville South High School and reached the final of the Illinois state championship in 2010 and winning the finals in his senior season in 2012.
He played for Loyola Ramblers for three seasons; 2013-2015. He reached the semifinals of the 2013 NCAA Men's DI-II National Championship, and won the 2014 and 2015 NCAA Men's DI-II National Championships. He was named to the NCAA All-Tournament Team in 2014 and 2015, and in 2015 he was named AVCA Player of the Year.[4] After his junior year of college, he interrupted his studies to sign a three-year contract with Polish club Asseco Resovia Rzeszów, who were the Polish Champions in the previous season.[5] This was his first professional contract of his career. Jaeschke would later sit out the first half of his second professional season to complete his college degree.[6] In 2017 he moved to Italian club Calzedonia Verona.