The four were eliminated from the competition by their mentors Louis Walsh, Gary Barlow, Tulisa Contostavlos and Kelly Rowland as part of this week's shock mass elimination.
When prompted for his vote, Walsh told host Dermot O'Leary that he found the decision "agonising", but ultimately had to "keep the [people] the public are going to like most".
The Irish producer then elected to send home Kerr, with the soldier-turned-singer admitting before leaving the show that he felt like he "could have done better" yesterday.
Next was Barlow, who described his boys as being at a "high level" before choosing to boot Michael. The teary-eyed guitarist vowed to "carry on with music" and continue chasing his dream of "performing to millions of people".
Contostavlos, meanwhile, narrowed her pick down to either Nu Vibe or 2 Shoes, eventually deciding to save the boyband so that they could improve on their 'disappointing' performance from last night.
However, the N-Dubz star insisted that she wanted to keep in touch with the Essex duo, who assured her that they were "so proud" to have even reached the live stages of the "amazing" competition.
Rowland concluded the voting by breaking down as she praised all of her "incredibly talented" girls and regretfully denied Lily a spot in next week's show.
The 16-year-old was too overcome with emotion to discuss her elimination with O'Leary, but Rowland had no problem spelling out her vision of Lily's future.
"You all are going to see this girl everywhere," she told the audience. "She has an incredible voice - she's bold, she's young."
The remaining 12 X Factor contestants will face the public vote for the first time next Saturday at 7.45pm on ITV1.