Following his graduation from Eastman, Garth spent several years in Chicago, where he enjoyed a highly successful career as a freelance musician. During this time he held the position of second trombone with both the  Chicago Sinfonietta and Elgin Symphony Orchestra, while continuing his studies in the Civic Orchestra of Chicago. Other notable performing credits include Sir Georg Solti’s Carnegie Hall Project, the Schlossfestspiele Heidelberg, Germany, the Chicago Opera Theater, and soloist with the Chicago Chamber Orchestra.

In 1997, Mr. Simmons left Chicago to become the principal trombonist with the Alabama Symphony Orchestra, a position he held until 2000. While in Birmingham, Garth was on the faculty of Birmingham-Southern College and the University of Alabama-Birmingham.

In addition to his duties with the TSO, Garth maintains an active schedule as a  soloist, chamber musician and educator. He is regularly featured as a soloist with the TSO, including performances of Christopher Rouse’s Trombone Concerto in March of 2008.   He  has presented numerous recitals as a visiting artist, including appearances at the University of Alabama, Northern Illinois University, Illinois State University,  and Northwestern University.  

From 2006 to 2017, Mr. Simmons was adjunct associate professor of trombone at Bowling Green State University. During this time he taught applied trombone, brass chamber music, and brass orchestral repertoire.

Garth can be heard on several recordings with the Chicago Sinfonietta, the Orchestra of the Assumption Grotto, and the  Asbury Brass Quintet. Mr. Simmons also performs frequently as a substitute and extra with the Detroit Symphony Orchestra. His debut solo CD, American Visions, was released in 2013 and is available at www.garthsimmons.com, CDBaby,  and Apple Music.

Zachary received his bachelor's degree from Appalachian State University, studying with Dr. Drew C. Leslie and Dr. Joseph Brown. He also holds a master's degree and an artist diploma from the Cleveland Institute of Music, under the mentorship of Randall Hawes and Peter Sullivan.

As a student, Zachary spent summers as an Orchestral Fellow at the Music Academy of the West; Aspen Music Festival and School, and the National Orchestral Institute + Festival. During the time he attended these festivals, his teachers included Weston Sprott, Mark Lawrence; John Engelkes, John D. Rojak; Matthew Guilford, Larry Zalkind, and Ken Thompkins.

He has performed a wide variety of solo literature, from Baroque music like Telemann's "Recorder Sonata in F minor", to contemporary Swiss composer Daniel Schnyder's "subZERO Bass Trombone Concerto", to American singer-songwriter and composer Frank Zappa's "The Black Page #1".