At seventeen Hornbrook was asked to join an early incarnation of Poison the Well dubbed Doubting Thomas.

[citation needed] After a brief hiatus with An Acre Lost Hornbrook rejoined the band and the name was changed to Poison the Well.

Then during his senior year, Poison the Well played a few shows up the east coast of the United States one weekend a month.

[7] Hornbrook has stated that he was "obsessed" with English rock band Queen drummer Roger Taylor when he first started playing.

[10] In an interview he did with The Washington Post during the promotion of the bands' fourth record "Versions", he stated, "I wanted to push the envelope.

[13] In early February 1999, Hornbrook joined Shai Hulud filling in as their drummer after the departure of Steve Kleisath.

Hornbrook performed with Shai Hulud for roughly three weeks including a one-off show at Middlesex County College in Edison, New Jersey on February 27, 1999, with Hatebreed, Cave In, The Judas Factor, Linus, As Darkness Falls and The Degenerics.

In 2012, Hornbrook was invited to perform live with electronic pop artist Big Black Delta.

[17] It was announced on June 2, 2014, via Alternative Press that Hornbrook would be replacing original Senses Fail drummer Dan Trapp on the band's tenth-anniversary tour of their seminal release "Let It Enfold You".

[18] It was revealed later that year that he would also be participating in the band's seventh studio record "Pull The Thorns From Your Heart".

[25][26][27][28][29] Hornbrook also makes an appearance on Harrison's live performance film "IN///PARALIVE" alongside musicians Davide Rossi of Coldplay, Stephen Perkins of Jane's Addiction, Big Black Delta, Camila Grey of Uh Huh Her and Mereki Beach.

[30] It was announced in early 2020 that Greg Puciato's first solo record: Child Soldier: Creator of God would predominately feature Hornbrook's drumming.

Out of the fifteen tracks on Child Soldier: Creator of God Hornbrook drummed on a majority of the record with Chris Pennie (ex-The Dillinger Escape Plan, Coheed and Cambria) and Ben Koller (Converge, Mutoid Man) drumming on a few other tracks.

[33] Hornbrook was in a drum play-through feature of "Deep Set" exclusively with Modern Drummer Magazine on May 27.