His family moved to Arlington Heights, Illinois, where he attended Rolling Meadows High School along with Yonder Mountain String Band’s Jeff Austin.

After high school they both attended the University of Illinois where they met Austin’s future bandmate Dave Johnston.

[1] Upon graduation Garrison moved to Colorado where he played in Fireweed with Austin and Johnston and in an early version of the Motet.

[5] In 2020 Garrison helped form bluegrass supergroup Mighty Poplar with Chris Eldridge, Alex Hargreaves, Andrew Marlin, and Noam Pikelny.

[8] In addition to his work with Leftover Salmon, Punch Brothers, and Mighty Poplar, Garrison has released three solo albums, 2011’s Low Lonesome, 2020’s Sycamore, and the co-led Bluegrass and the Abstract Truth in 2022.