After their success, the band decided to move on to solo projects. Gately was the first, with his debut solo single, "New Beginning", released on 29 May 2000. The single reached number three in the UK charts.
In January 2007, Gately was heard in Horror of Glam Rock, a Doctor Who audio drama produced by Big Finish Productions for BBC7. For this audio play, Gately recorded an original song, "Children of Tomorrow", with music by Tim Sutton and lyrics by Barnaby Edwards; this was his first solo track since 2001.
In 2008 following his solo career and various bouts of acting and television appearances, Gately rejoined his old colleagues when Boyzone reformed, following the success of revived contemporaries Take That. Gately had been the most eager to reform and urged his bandmates to come together again. They sold out two more tours of the United Kingdom.
Boyzone released a brand new single, "Love You Anyway", followed by a new compilation album in October 2008. December 2008 saw the release of a second new single, "Better". The video for the song generated controversy, as scenes depicting romantic couples included a shot of two men embracing, in an inclusive nod to Gately's homosexuality. The group unanimously agreed that Gately should be allowed to pair with a male actor. It was condemned by, among others, the minister of the Dromore Reformed Presbyterian Church. Others, however, cite that milestone as among the reasons why Gately is a "gay rights hero". Wrote Tim Teeman of the Times Online, "Gately showed that an unflamboyant guy could be a pop star and gay...the real shame should be reserved for those managers and show business power-brokers who practise that kind of discrimination, and also maintain the closet, to line their pockets."
Gately was a vice patron of the charity Missing People (formerly National Missing Persons Helpline), supporting their Runaway Helpline service for young people. He was an ambassador for the Caudwell Children Charity in Stoke and on one occasion gave a private Christmas performance, raising thousands of pounds. Gately's family requested that donations be given to the charity instead of flowers sent to them after his death in 2009. This in turn raised thousands more pounds. On one visit to a hospital he met a child who fell in love with his jacket — Gately allowed her to have it; she was dead within the hour.
During the three years prior to his death, Gately had been writing a children's fantasy novel called The Tree of Seasons. In an April 2009 interview with the Press Association he declared that he was nearly finished, had publisher interest, and hoped for a Christmas 2009 release. Boyzone bandmate Ronan Keating promised at Gately's funeral that "by hook or by crook" the book would be finished.
The Tree of Seasons was written in collaboration with June Considine and Jules Williams. Based on Gately's handwritten notes - the day he died he had just worked out the ending. The book released in the UK and Ireland on 13 May 2010, published by Hodder & Stoughton. It contains a foreword by Elton John and David Furnish, and is illustrated by Keith Wilson. The Tree Of Seasons remained a best seller and a top ten seller for three consecutive weeks. The Paperback version will be released in April 2011
Gately wed Andrew Cowles, first in a commitment ceremony in Las Vegas in 2003 and more formally in a civil partnership ceremony in London in 2006.
On 6 October 2009, Gately had posted on Twitter, saying: "Still busy, lots going on. Focussing on finishing my book next so may be quiet here." He had attended the Pride of Britain Awards in London before flying to his apartment in Majorca.
Gately's body was discovered on 10 October 2009 in the apartment which Gately owned with Cowles near Port d'Andratx on the western tip of Majorca in Spain. He died of natural causes due to pulmonary oedema.