During academic year 2006–2007, Thornock was a visiting assistant professor of music and assistant to the Provost for accreditation at Southern Virginia University. He joined BYU's School of Music faculty during the 2007-2008 academic year. In 2015, he was announced as the new associate director of the School of Music over undergraduate studies. He teaches courses in composition and theory.
In his artistic pursuits, Thornock primarily considers himself a performer/composer. Many of his compositions grow out of performance opportunities on organ, carillon, piano, toy piano, and harpsichord. His interests also include electronic sound media (including Huygens’ Workshop for toy piano and electronics) and growing interest in video. Thornock’s works have been described both as richly scored, moving, and resonant and as possessing cool understatement.
In 2004, Thornock was awarded a Barlow Commission which resulted in a 35-minute double bass solo, premiered at Indiana University by Nathan Wood. Additionally, his music for carillon has garnered several international awards and has been regularly performed at congresses of the Guild of Carillonneurs of North America since 2001. In 2001 and 2003 he was awarded Oscarson Discovery Grants that allowed his participation in the Congress of the Guild of Carillonneurs of North America for those two years.
In 2011, Thornock and Steven Ricks collaborated to complete the Matthew Coley Residency Project, funded by the Laycock Center for Creative Collaboration in the Arts. The project brought award-winning percussionist Matthew Coley to BYU for a few days. While he was at the school he performed new pieces composed by Thornock and composition students. Midway through the week, Coley and Thornock recorded Thornock's two percussion pieces, Dulci and Litany for John Cage; this first recording was the beginning of a more extensive collaboration to record all of Thornock's pieces for a CD released at the end of 2012. Earlier that year, he worked with the New York Piano Trio during their residency at BYU, which funded by the Laycock Center.
Thornock was again awarded an LDS Barlow Commission in 2015. The same year, he also received funding from the Laycock Center to host four events for the BYU Centennial Carillon 40th Anniversary Festival held from September through November 2015.
He and his wife, Tammy, have five children.