[1] The group is the husband-and-wife team of Kori Gardner (born June 16, 1974) (vocals, organ, synthesizer, piano, electric piano, and occasional guitar and drums) and Jason Hammel (born February 1, 1976) (vocals, drums, percussion, and occasional synthesizer).

Both had started out playing the guitar, but they ultimately found they were experimenting more with the organ and drums in their practice space than with any other musical instruments.

On later recordings, the band moved away from the organ-dominated sound and incorporated additional instrumentation, beginning with the EP All Day and continuing on Bring It Back, their fourth studio album.

On October 11, 2004, the band held a contest for fans to create their own video for "Goods (All In Your Head)," the first track on their All Day EP.

The winning entry, directed by Jonathan Yi and Sam Goetz, became the official video for the song [9] and was aired on MTV on June 12, 2005.

[10] For their tour in support of the album, Mates of State became a quartet by adding Lewis and Anton Patzner of Judgement Day as multi-instrumentalists[11] to complement the duo's sound on select songs.

In the summer of 2001, they played shows with Superdrag and Beulah and, later in the year, opened for The Anniversary during the release tour for their album Your Majesty.

[17] Mates of State also provided support (alongside Au Revoir Simone) for We Are Scientists on their tour of the UK in November 2006.

[18] During February and March 2007, Mates of State toured as the house band for WBEZ Chicago's This American Life, hosted by Ira Glass.

[25] Beginning in 2010, the band toured with backing musicians Kenji Shinagawa on guitar and John Panos on trumpet, both graduates of the University of Miami.

[26] On June 11, 2013, they joined The Postal Service's "Give Up" ten-year reunion tour at the Air Canada Theater in Toronto.