The 32-year-old had a record deal with Universal Music, releasing three singles, appearing on Top of the Pops in 2002 and touring with Kanye West and R Kelly.
Despite his fall from the limelight, Henry revealed backstage that his resurgence has been spurred by the death of his younger brother Vivian aged 19, following a heart condition.
"What made everything come to a stop was the passing of my little brother. I suppose I didn't recover from it, in a sense," he said.
"I'd give my all to get back to my career. My brother was a big fan of my career. I just feel like I'm letting him down. This is my way to make him proud of me."
Covering Ne-Yo's 'Closer', Henry impressed Jessie J and The Script's Danny O'Donoghue, while Sir Tom Jones and will.i.am decided not to turn their chairs around.
The soul singer was eventually persuaded by Jessie J's insight. The 'Price Tag' singer had said: "I turned around because there was something in your voice I heard that I really, really liked.
"But for me, if you were on my team, I'd [improve] the upper range and your breathing, and the way you hold the mic is wrong. I just think you've got a really listenable voice."
After will.i.am advised Henry to choose O'Donoghue, Jessie J added: "I've been signed for seven years, this industry is about learning who you need around you. Someone who knows how to work a stage."
Watch Cassius Henry sing Ne-Yo's 'Closer' below: