Early years

Threat Signal was formed in the late summer of 2003 by cousins Jon and Rich Howard, who then added composer/guitarist Kyle McKnight. The trio then found drummer Adam Wood in early 2004. Threat Signal posted their song "Rational Eyes" on an international metal chart on GarageBand.com. After a few weeks, the song reached #1, and it has received many awards including best guitars, best drums, best male vocals, best production, song of the week, and song of the day. In August 2004, Eric Papky, Kyle's former guitar teacher, joined the band on bass. Success on GarageBand.com sparked some early record label interest and helped create a following even before the band had ever played live. In August 2005 Marco Bresette replaced Eric Papky on bass guitar.
Nuclear Blast and Under Reprisal

After spending the better part of 2004 and 2005 writing and recording demos, the band traveled to Los Angeles, to record with Christian Olde Wolbers of Fear Factory in September, 2005. In November 2005, the band announced they had signed a recording deal with Nuclear Blast records. In late 2005 Adam Wood left the band, and he was replaced by Pittsburgh, Pennsylvania native George Parfitt. In July the band took part in Germany's Earthshaker Fest, alongside notable acts as Scar Symmetry, Communic, and Arch Enemy. On August 1, 2006, the band announced that guitarist Rich Howard had left the band to pursue other personal goals, and he was replaced by the band's bassist, Marco Bressette. This left the bass guitar duties vacant, and in late September Pat Kavanagh was announced as the new bassist. In October, the band began a North American trek with Soilwork, Mnemic, and Darkest Hour. The tour ended in November, but the band announced a headlining tour of North America in early 2007 as well.
New material, touring and line-up changes

In March 2007, Threat Signal began demoing new material, but was hampered by second departure, this time Marco Bressette's. The band announced a search for a new guitarist the same day, while guitarist Adam Weber would join the band temporarily to fill in for the remaining tour dates. Threat Signal was tapped as the opener for the Tour and Loathing trek alongside Protest the Hero, All That Remains, Blessthefall, and The Holly Springs Disaster. Shortly after this tour, guitarist Kyle McKnight parted ways with Threat Signal in June 2007 due to personal differences with the remaining members of the band. The band's drummer, George Parfitt, also departed later in 2007 to focus on his family life. The remaining members of band, Jon Howard and Pat Kavanagh reformed the band’s line-up with the new additions of drummer Norm Killeen and guitarists Travis Montgomery and Adam Weber.

In 2008 Jon Howard and Pat Kavanagh joined Arkaea alongside ex-Fear Factory members Raymond Herrera on drums and Christian Olde Wolbers (who produced Threat Signal's debut Under Reprisal) on guitar.
Vigilance

Threat Signal's second album Vigilance, which was produced by Howard (who is now the only founding member left in the band) and mixed by Greg Reely, was released on September 8, 2009 in North America and September 11, 2009 in Europe. The album spawned a music video for the track "Severed". On July 15 the band released a 32 minute "making of" video for the new record, containing footage of the recordings, song writing process and interviews with band members. The album sold around 1,100 copies in its first week of sale in the United States, with the band touring alongside Epica and later Dark Tranquillity to support the album.
Second lineup change

In July 2010 it was confirmed that Adam Weber had quit the band. Pat Kavanagh (bass, vocals) has issued the following statement:

“Adam has decided to leave us. He has some personal things he needs to work out and we wish him all the best. We’re still good friends and there’s plenty more beers that we’ll have together so no worries. I know this sucks to hear for a lot of you and I can list off a boat load of bands that have been through the same s*** we’ve been through. Just know it sucks hard on our side too. On a positive note we have a huge head start on the next record. Even have a few demos already! You’ll be hearing new s*** soon. So we hope to see you on the road with Soilwork, Mutiny Within and Kris Norris soon! Good times will be had by all!”

Ex-Darkest Hour guitarist Kris Norris filled in for Adam's absence

On September 13, 2010, The band posted an online statement that they also parted ways with drummer Norman Killeen. Both Adam and Norman were eventually replaced by drummer Alex Rüdinger and guitarist Chris Feener.
Recording Third Album

The band announced on their Facebook page that the third album will be produced and mixed by "musical mastermind" Zeuss (Chimaira, Hatebreed, All That Remains, The Acacia Strain, Born Of Osiris, Shadows Fall, etc.). They also stated that they have been experimenting with 7 string guitars on this album. The band is quoted saying: "We are headed back to the Under Reprisal days but with bigger balls." The band also stated that it will be a self-titled album.

Threat Signal's self-titled new album "Threat Signal" was released on October 7, 2011 in Europe and on October 11, 2011 in North America.