Growing up, I fantasized about being a rock musician and that somehow it would be really easy. I didn't realize that it's so much work.

Julian Lennon is his half-brother and Kyoko Chan Cox is his half-sister. On October 22 2011 Sean showed up on Wall Street with Rufus Wainwright and Josh Fox. The Ghost of a Saber Tooth Tiger
Kemp Muhl and Lennon premiered the band The Ghost of a Saber Tooth Tiger during a live performance at Radio City on Valentines Day 2008.

He is the only child of John Lennon and Yoko Ono making him the half-brother of Julian Lennon and Kyoko Chan Cox. His godfather is Sir Elton John.