Having never privately studied composition until after his graduation from IU, Matt Riggen's knowledge of how to write and arrange came largely through
assimilating the voice-leading rules of European art music via music theory courses at Indiana University,
studying the writing of Charles Ives and Duke Ellington in his own time, two classes spent with master composer/arranger Brent Wallarab,
and allowing himself to be obsessive about the creative process by writing at least 25 small-group tunes every year from age 18 to age 22.

His first large-ensemble works were workshopped with the Wayne Wallace Ensemble at Indiana University,
and his first public outings of big band works on the co-led Liberation Music Collective record Siglo XXI received considerable acclaim
and were partially responsible for that group receiving a prestigious ELU from France's CitizenJazz.

He was the LMC's main composer on their critically acclaimed jazz opera UTOPIA, produced in collaboration with
the IU Jacobs School of Music's Project Jumpstart and public radio host Yael Ksander.

His work co-composing for the Liberation Music Collective's second record, Rebel Portraiture, 
led to a running formal partnership with the Indianapolis-based Sean Imboden Large Ensemble.
Riggen is one of several 'local composers' who have an open door to bring compositions and arrangements
in to be performed by this group of Indiana giants (including Rob Dixon and Freddie Mendoza).

In late 2017 through mid-2018, Riggen was invited to and subsequently took part in the BMI Jazz Composer's Workshop in NYC,
which is an organization founded in part by Bob Brookmeyer to give composers an arena in which to experiment and test their ideas and concepts.
As a consequence of this, Riggen loosely studied with Andy Farber and Ted Nash,
along with getting a chance to hear his most recent works performed by the BMI Jazz Composer's Orchestra in a reading-band context.
A second year was spent working with the Workshop in 2018-2019, where the directors were Andy Farber and Alan Ferber.

Most of the small-ensemble work Riggen does as a performer also showcases his writing as an extension of his membership in the group, as in his work with the Sean Imboden Quintet and OGC.

Currently, Riggen is working on a full-length suite, underwritten by Chicago's Department of Cultural Affairs and Special Events,
which is entitled A History of Violence in the United States. It explores the country's maladaptive process towards mass death, specifically in the context of spree shootings.

In early 2020, Riggen's long isolation due to COVID-19 led to several entirely self-made recording projects,
​exploring ideas which his directorship at Marquette Park would normally take priority over. 
These include a full scoring of "I Sing The Body Electric", "Alone Again", "How Dare You?", "Cycles for America", and "Many As One". Each will receive an album release.

After 2020, much of Riggen's compositional energy has gone directly into the Marquette Park Composer's Workshop,
which can be read about more in the "Director" section of this website.