Matt Thiessen

In addition to being in Relient K, Thiessen plays in his own solo piano project called Matthew Thiessen and the Earthquakes. Prior to 2018, the project had released a total of five songs on various samplers and compilation albums from Gotee and Mono Vs. Stereo, and several songs written for the project have been re-recorded on Relient K releases. In 2010, after the release and supporting tour of Forget and Not Slow Down, Thiessen announced that he would begin work on a full-length solo album. Although he had previously expressed interest in recording a studio release, he had placed his priority on Relient K, and relegated his solo work to his free time.

In April 2018, Adam Young of Owl City announced that Matthew Thiessen and the Earthquakes would be joining them on tour later in the year. In June 2018, Thiessen announced that his debut album under Matthew Thiessen and the Earthquakes, Wind Up Bird, would release later that summer.

Thiessen married Emily Wright on August 23, 2015 in New York City, with Matt Hoopes as his best man. They kept the engagement and marriage a secret from the public.

In 2009, he contributed vocals, songwriting, and production to Owl City's major-label debut Ocean Eyes, which has sold over 1,500,000 copies worldwide and reached the top ten on the Billboard 200. Lead single "Fireflies" reached number one on the Billboard Hot 100 in late October. Thiessen continues to work with Owl City's Adam Young and contributes vocals to "Plant Life", a song on the album, "All Things Bright and Beautiful". He also co-wrote "Good Time" with Owl City and Brian Lee. Thiessen has also made guest contributions on a number of releases with other artists, including Blackbear, John Reuben, tobyMac and The Fold.

In 2008, it was announced that Thiessen proposed to Shannon Murphy, a morning radio co-host of the "Mojo in the Morning" show based in Detroit. The couple planned for an August 22, 2009 wedding. However, the engagement was terminated in December, after Murphy claimed that Thiessen had been unfaithful.

Thiessen has occasionally collaborated with Jon Foreman of Switchfoot. After initial interest in recording vocals for a Switchfoot song, it instead worked out for Foreman to contribute vocals for the Relient K song "Deathbed" from Five Score and Seven Years Ago. He later contributed songwriting and vocals to the Switchfoot release "Rebuild" in 2007, in conjunction for the Appetite for Construction Tour.

Thiessen dated future pop star Katy Perry for a time from 2003 until 2005, and wrote several songs with her and Glen Ballard during her early recording sessions. One of the songs the three wrote, "Long Shot", would go on to be recorded by Kelly Clarkson on her 2009 album All I Ever Wanted. Remaining on good terms with Perry, he also co-wrote "Dressin' Up from Teenage Dream: The Complete Confection.

For all of Relient K's history, Thiessen has been the lead vocalist, frontman, guitarist, primary songwriter, and sometime co-producer. Because of this position of musical leader, he maintains the most creative and artistic control of the band members. He has also been credited with piano in most releases, beginning with The Anatomy of the Tongue in Cheek in 2001. Since the release of Mmhmm in 2004, his piano playing started becoming more prominent, and he began including a piano onstage as well.

Thiessen founded Relient K in 1998, with guitarist Matt Hoopes, and bassist Brian Pittman, and recorded the demo All Work & No Play the same year. The recording attracted the interest of Toby McKeehan who signed the band to his label Gotee Records. Between the years 2000 and 2003, Gotee released three full-length albums, one Christmas album, and four EPs with Relient K. In 2004, their fourth album Mmhmm was released on both Capitol Records and Gotee, and peaked at number fifteen on the Billboard 200. After recording another EP in 2005, Mmhmm and Two Lefts Don't Make a Right...but Three Do, their 2003 album, were certified gold, followed by their 2001 album The Anatomy of the Tongue in Cheek in 2006. In 2007, Gotee, Capitol, and EMI released Relient K's fifth studio album, Five Score and Seven Years Ago, which peaked at number six on the Billboard 200. After the release of the double EP The Bird and the Bee Sides in 2008, the band signed with Gotee's Mono Vs. Stereo imprint, on which they released their sixth studio album, Forget and Not Slow Down, again reaching the top twenty of the Billboard 200. Thiessen and the other members of Relient K have taken up A&R positions for the label as part of the record deal.

Matthew Arnold Thiessen (born August 12, 1980) is a Canadian-American musician, singer and songwriter known for being co-founder, lead singer, guitarist, pianist, and primary songwriter for the Christian rock band Relient K. With Relient K, he has released eight full-length albums, including three that were certified Gold, and three that peaked in the top twenty on the Billboard 200. Outside of his work with Relient K, Thiessen leads a side project called Matthew Thiessen and the Earthquakes, which released its debut album Wind Up Bird on August 31, 2018. In 2009, he co-produced and collaborated on Owl City's album Ocean Eyes.