Danny said: "I had two wonderful seasons on The Voice and as everybody knows I gave it my heart and soul and couldn't be more proud of the show and what we have achieved.
"My focus will be on The Script moving forward as we are about to embark on the most important part of our career as a band."
Mark Linsey, the BBC's controller of entertainment commissioning added: "Danny has been an absolute star – and a winner - on The Voice but we understand that he, like Jessie, has to focus on his music career and The Script have such an incredibly busy year ahead.
"The Voice coaches are all current music stars with recording and touring careers to manage alongside the show and we know this can be difficult to juggle.
"We are very sorry to see Danny go but wish him and the band the very best and hope they will come back and perform for us next series."
Danny is the second of the coaches to quit the show this year, after Jessie J announced last month that she too would not be returning for a third series.
JLS' singer Ortise Williams, Rita Ora and Emeli Sande have been touted as possible replacements on the panel.
A spokesperson for The Voice UK remarked that negotiations with the remaining two coaches, Will.i.am and Sir Tom Jones, were still ongoing.
The Voice 2014 will air on BBC One next Spring.