It features music written by drummer Matt Cameron with lyrics co-written by Cameron and lead singer Eddie Vedder. Cameron plays rhythm guitar on the studio version. Cameron created the song's music by feeding his guitar through a drum machine. As a result, the song features a reverb-soaked guitar sound and a swaggering beat. Cameron and bassist Jeff Ament both compared the song to The Smiths' "How Soon Is Now?".

Matt Cameron on the song:

I just recorded that at home. I had written just a couple of riffs, stringing them together like I always do. I had gotten a new drum machine that allows you to make up patterns and then they'll play through whatever audio instrument you plug in. It was more of an experiment to use the parameters of this machine as well. It came out really cool and the guys really liked it. I took my machine down to the studio, dumped it into the computer, and did an arrangement. Eddie finished up the small bit of lyrics I had written for it.

According to the liner notes for Lost Dogs, the song's original title was "Undone". When the song's title was changed to "You Are" Vedder borrowed the original title for the song "Undone".

The song was an album track pick at Allmusic, along with "Save You" and "Love Boat Captain". In its review of Riot Act, The Guardian stated that the song "is constructed over an intriguing, reverb-heavy funky beat and offers a rare chance to hear Eddie Vedder singing instead of making dismal groaning noises." Kyle Reiter of Pitchfork Media said, "The mechanical, pulsating guitar arpeggios of "You Are" almost seem to cop from Trans-era Neil Young until you realize that it'd set a nice ambiance for a semi-truck barreling down a highway in Stallone's Over the Top."

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