"I Wanna" was written by Nick Wheeler and Tyson Ritter in Florida, United States and was one of the first songs to be written and recorded for When the World Comes Down within a six-month time period both in the studio and the band's tour bus and was refined by Ritter numerous times before recording began.
In an interview with Take 40 Australia, Wheeler said "Tyson came up with the idea on the road while we were touring Move Along. Two years straight on the road, barely going home. And when all you see is planes, buses, cars, insides of venues, dressing rooms and hotels... it starts to feel like a prison. That's kinda what the song's about... you're locked away in this hole and all you wanna do is touch somebody."
The song received mixed reviews from music critics. The Impressive Inklings praised the song as an album opener and praised Ritter's vocal work as "impressive", while Marshall Lately stated that the track is "a playful opener on the junior effort" and "is repetitive without being annoying, which is seldom found in pop ditties, [it] shows lyrically that they know where they came from, but also where they’re going."
Sputnikmusic were more negative, stating "'I Wanna' has enough cringe-inducing lyrics to fill a Mariah Carey song and Ritter’s delivery is bored, at best. It feels as though AAR is tired with this same old song-and-dance routine"
Worldwide, "I Wanna" achieved moderate success, peaking at #42 and #45 in Austria and Germany respectively and #84 in the United Kingdom. In Australia, the song became The All-American Rejects' second-highest charting single in that territory - following "Gives You Hell" - peaking at #15. It also charted in the country's year-end Top 100 Singles at #88.
A music video for "I Wanna" was directed by Rich Lee and was shot in June 2009 and was released a month later in mid-July. It primarily features the band performing the song on the set of their I Wanna Rock Tour stage set-up with neon lights, while scenes of a couple listening to music and sitting in a car are overlapped through the video, leading to them performing sexual intercourse.
A second version, directed by Paul Hunter, was released October 13, 2009. It revolves around a house party with the band where lead singer and bassist Tyson Ritter encounters his ex-girlfriend (played by Julianna Guill) with a new boyfriend. Throughout the video, a series of videos and transitions are shown on LG cell phones that show the video both through them and how Ritter and his girlfriend broke up. Towards the end, The All-American Rejects are seen performing in front of their party guests with Ritter and the ex-girlfriend crowd surfing towards each other in the audience and ultimately renewing their relationship when they reach each other.