James Matthew Dewees (born March 13, 1976) is an American musician best known for his work with The Get Up Kids, Reggie and the Full Effect and My Chemical Romance.

[1] In 1997, Coalesce played a music festival in Wilkes-Barre, Pennsylvania with fellow Kansas City band The Get Up Kids.

An audience member then tried to steal the drum, so Dewees began chasing them, aided by The Get Up Kids' guitarist Jim Suptic.

After the release of the band's second album Something to Write Home About, The Get Up Kids began receiving much greater national attention.

In order to capitalize off of the success of Something to Write Home About, as well as bridge the gap between their next album, the band released a collection of B-sides and rarities, entitled Eudora, in 2000.

The album was met with a much warmer reception than On a Wire, but there was a great deal of tension between the bandmates during their world tour supporting the release.

Lead singer Matt Pryor, whose wife had recently given birth, wanted to spend more time at home.

As the title suggests, the album was recorded at the Granada Theater in Lawrence, Kansas at the band's tenth-anniversary show.

After this was a huge success the album titled No Country for Old Musicians was released in November 2013 under Pure Noise Records.

In 2007, he joined My Chemical Romance as their touring keyboardist, becoming an official member albeit for a short period of time in 2012 until the band's split in 2013.

The collaboration grew into several East Coast tours in early 2013, and a self-titled EP as 'Matt Pryor and James Dewees' that October.

There have been five Common Denominator songs on Reggie and the Full Effect albums; "Dwarf Invasion" on Promotional Copy, "Linkin' Verbs" on Under the Tray, "Deathnotronic" on Songs Not to Get Married To, "Dmv Featuring Common Denominator" on No Country for Old Musicians, and "Trap(ing) Music" on 41.