Taylor previewed this upbeat track on the October 1, 2012 episode of ABC's Good Morning America. The song finds the Country-Pop star playing with the idea of colors in relation to her emotions about a former beau, as she sings: "Losing him is blue, like I'd never known. Missing him was dark grey, all alone. Forgetting him was like trying to know somebody you never met. But loving him was red." Before playing the track, Swift explained its meaning: "I wrote this song about the fact that some things are just hard to forget," she said, "because the emotions involved with them were so intense and, to me, intense emotion is red." Swift explained that she decided to name the this song as her album title, as its lyrics encompass the entire theme of the project. "Thinking about what that means to me and all the different emotions that are written about on this album - they're all pretty much about the tumultuous, crazy, insane, intense, semi-toxic relationships that I've experienced in the last two years," she noted. "All those emotions - spanning from intense love, intense frustration, jealousy, confusion - in my mind, all those emotions are red. There's nothing in between; there is nothing beige about any of those feelings." She explained to Billboard magazine. "I think the reason I said that was because I made the record exactly the same way I made the last three. I knew I hadn't jumped out of my comfort zone, which at the time was writing alone and working with Nathan. [Red] the song was a real turning point for Red the album. When I wrote that song my mind started wandering to all the places we could go. If I were to think outside the box enough, go in with different people, I could learn from and have what they do rub off on me as well as have what I do rub off on them."
"Red" received positive reviews from music critics, most praising Swift's strong lyrics but criticizing her usage of autotune in a portion of the song and disapproving her treading into too many genres at once. Marc Hogan of Spin felt the schizophrenic influences didn’t work in Swift’s favor: “A glossy soft rocker with a stomping four-on-the-floor beat, back-porch twang, adult-contemporary orchestration, and Top 40-ready electronic vocal effects, it covers a bizarre number of bases. And the key lyric compares her lost love, mourned here as an object of desire but not kissed off as one of the usual jerks, to ‘driving a new Maserati down a dead end street,’ like Swift is about to brawl with Rick Ross.”  Grady Smith of Entertainment Weekly, joked, saying: "Those are the only colors the song — which Swift says is all about 'intense emotion' — brings up, which kind of let me down. (...) I’m being serious — I kept waiting for some other hue to pop up, and it never did.(... And then, said: "Lyrically, (...) [some] lines (...) lack the crisp, powerful punch that Swift usually delivers. And in a song all about the vividness of feelings, they paint a rather blurry portrait. (...) Where is the drama, the sexiness, the freefall of passion? The poppy production white-washes over all that. That doesn’t mean this is a bad song, just maybe an underwhelming one."
Rebecca Macatee of E! Online, found the lyrics to be a rainbow of fruit flavors: ”She…goes through myriad colors to describe her feelings… We’re not sure what color Swift’s heart is, but we’re sure it’s pretty.” Laurence of Music City Post, noted the track’s melodic strength: “With a lot of heart on the sleeve lyricism (...) and a hefty guitar solo, ‘Red’ does nothing by half measures."Rolling Stone responded favorably to the record, noting that the song marries her heartbreak anthems with a radio-friendly sound "with banjos flying, strings swelling and guitars wailing, Swift keeps her lyrics simple but effective[.]"The Pop Fairy gave a negative review: "“Red” is (...) another love song by America’s favorite cougar of the moment. (...) The only unique thing about the song is the thing I can’t stand, the electronic ‘R-R-Red’ that repeats after the chorus.” Finishing with 'A little more effort would be nice.', giving the song a grade 'C'.