Taylor released her third studio album, Speak Now, in October 2010. She wrote the album entirely by herself and co-produced it with Nathan Chapman, her longtime collaborator. That album musically expands on the country pop sound of her two previous albums, with elements of radio-friendly pop crossover that had been evident on its predecessor Fearless (2008). On Speak Now‘s follow-up, RED, Taylor aimed to experiment beyond her previous albums’ formulaic country pop sound. To this end, she approached different producers beyond her career base of Nashville, Tennessee.
Although Taylor wanted to experiment with various musical styles, she, as a songwriter, prioritized the lyrics over the production, striving to capture her temporary emotions. She went to Los Angeles to meet with Swedish producer Max Martin, whose chart-topping pop songs had impressed her by “how [they] can just land a chorus”. For “I Knew You Were Trouble”, Taylor developed the song as a ballad on piano, and asked Martin and Shellback to accompany the intense emotional sentiment with a “chaotic” sound. She told Rolling Stone in 2020:
«I remember bringing in this slow, sad thing that I had written, called ‘I Knew You Were Trouble.’ I had originally called it ‘Trouble’. I was like, ‘I don't know if we could have some kind of intense bass drop or something, like dubstep is really awesome…’ And they were just like, ‘Yes, absolutely!’ And then Shellback was like, ‘In the verse, let's do this really frantic drum beat.’ And it just was something I would never have thought of; to make the beat of the verse really up-tempo, and then make the intensity drop off the chorus, and then have it build back up, and then have a production explosion at the end of the chorus. It was so thrilling! I couldn't believe the song started where it started and then their added ideas with production. They ended up seeping into my brain and I started thinking the way that I would hope they would think. I would write a verse and Max would be like, ‘This is this many syllables, can you shorten it and make it more succinct, but convey the same message?’ And I would just go off into a corner and I felt like I had like this amazing assignment. So the challenge of it was so thrilling for me.
«'I Knew You Were Trouble.' was a big signal flare. When I did something like that, that I thought people were going to be freaked out over, and it ended up spending seven weeks at No. 1 on the pop charts, it felt like I had tried on something new that fit really well.»
Taylor Swift
[Verse 1]
Once upon a time, a few mistakes ago
I was in your sights, you got me alone
You found me, you found me, you found me…
I guess you didn’t care and I guess I liked that
And when I fell hard, you took a step back
Without me, without me, without me…
[Pre-Chorus 1]
And he’s long gone when he’s next to me
And I realize the blame is on me, ’cause
[Chorus]
I knew you were trouble when you walked in
So shame on me now
Flew me to places I’d never been till you put me down
Oh, I knew you were trouble when you walked in
So shame on me now
Flew me to places I’d never been
Now I’m lying on the cold hard ground
Oh oh, trouble, trouble, trouble
Oh oh, trouble, trouble, trouble
[Verse 2]
No apologies, he’ll never see you cry
Pretends he doesn’t know that he’s the reason why
You’re drowning, you’re drowning, you’re drowning…
And I heard you moved on from whispers on the street
A new notch in your belt is all I’ll ever be
And now I see, now I see, now I see…
[Pre-Chorus 2]
He was long gone when he met me
And I realize the joke is on me
Hey!
[Chorus]
I knew you were trouble when you walked in
So shame on me now
Flew me to places I’d never been till you put me down
Oh, I knew you were trouble when you walked in
So shame on me now
Flew me to places I’d never been
Now I’m lying on the cold hard ground
Oh oh, trouble, trouble, trouble
Oh oh, trouble, trouble, trouble
[Bridge]
And the saddest fear
Comes creeping in
That you never loved me
Or her…or anyone…or anything
Yeah
[Final Chorus]
I knew you were trouble when you walked in
So shame on me now
Flew me to places I’d never been till you put me down
Oh, I knew you were trouble when you walked in (You were right there, you were right there)
So shame on me now
Flew me to places I’d never been
Now I’m lying on the cold hard ground
Oh oh, trouble, trouble, trouble (Trouble, oh)
Oh oh, trouble, trouble, trouble
[Outro]
I knew you were trouble when you walked in
Trouble, trouble, trouble
I knew you were trouble when you walked in
Trouble, trouble, trouble