This is the first single from Linkin Park's fourth album, A Thousand Suns. The song was premiered in the trailer of Electronic Arts' video game Medal of Honour on August 1, 2010 a day before the song was released. The band's DJ Joe Hahn directed the trailer. Linkin Park's music has appeared in other EA games such as the Madden football franchise. Bassist David "Phoenix" Farrell told USA Today: "When we were talking with EA and being familiar with the 'Medal of Honor' title I think the song made a lot of sense. The song itself has got some dark undertones and it's got a lot of energy in it. It kind of just fits with the subject matter."

Linkin Park held a contest during July 2010 in which fans could download stems from the song, remix the stems and/or write their own part for the song on any instrument. The prize was that winning remix would be featured on A Thousand Suns. The winner of the competition was NoBraiN, and his remix is included as an additional track on the album.

Bassist Dave "Phoenix" Farrell told MTV News that this moody rumination on the broken times in which we live was chosen as A Thousand Suns lead single as it indicates how the album is a drastic departure from anything the band have done in the past. "We wanted a track that represented where the album was going to be and how it was going to work, and this was really the track to do that. ... It's a risk, but [it's] worth it," he said. "We've known [the album is] going to be different, and if fans were expecting Hybrid Theory or Meteora, they're going to be surprised. It's going to take people some time to figure it out and know what to do with it."

The video for the song was filmed in June 2010 and was directed by Joe Hahn. Rapper and rhythm guitarist Mike Shinoda explained the clip to MTV News: "The concept to the video: If you could imagine when nuclear fission was invented, or a moment in time when something can be used for positive or negative. Something can be beautiful or it can be destructive. Or even if you've ever seen a dangerous fire from far away, it's devastating up close, but from far away, it can be beautiful. Those are the kind of themes that run throughout the album, and they're also themes that you see in the video."

The opening couplet, "God bless us every one/ We're a broken people living under loaded gun," is repeated several times throughout the song. It can also heard in A Thousand Sun's opening number "The Requiem."

Linkin Park bassist Dave "Phoenix" Farrell discussed the song's meaning and how it all came together in an interview with Artist Direct: "We were in the process of narrowing down tracks in the studio, and 'The Catalyst' in particular - even as a working track - was something we felt would be very important to the record. You can hear the lyric 'A thousand suns' in the song a couple of times. Obviously, we loved the idea of that and the imagery behind it. A Thousand Suns ended up becoming the album title. In 'The Catalyst,' people will draw different themes from it lyrically that continue in the record as a whole. That's one of the things we did a bit differently with this process. The intention was to create a 45-minute immersive 3-D world with the entire album. Things you begin to pick up on or questions that start to be raised when people listen to 'The Catalyst' come back. That conversation continues with the entire record. The songs interplay off of one other. The album intentionally hearkens back to what an album was meant to be in the '70s or the '80s. It's not a concept an album in the sense of Tommy, but there are concepts throughout the record that do carry a through line."

A Thousand Suns was a worldwide hit. Amongst the countries it topped the charts in were Australia, Austria, Canada, Germany, Japan, Korea, New Zealand, Singapore, Switzerland and the United States.