Frontman Luke Pritchard told the Independent newspaper May 9, 2008 about the lyrics for this song: "'When I look back on it and when I sing it on stage, on reflection, that's probably when I've written my most soulful lyrics. It's about first love - it's as simple as that. I hold simplicity in a high place. One of the things is trying to say a whole lot in a short amount of time. I write reams of words of what I might write in two verses. You want to make every word count. You often don't need words to know what the song is about."
"Lean On" was originally sent by Major Lazer to both Rihanna and Nicki Minaj's camps as a slower reggae track. After both parties rejected the tune, Major Lazer recruited Danish singer MØ to supply vocals and recorded it themselves.