The announcement was on the singer's website. It is her third marriage
"We who run this site are very happy to announce the marriage of Steve Cooney and Sinéad O'Connor has taken place this morning," reads the official statement.
"Thanks be to the Great Lord Jah. Rastafarai.
Dread I. Conquering Lion I. One love" the statement said on website www.sineadoconnor.com which also showed a picture of the happy couple kissing.
A close friend told the Irish Independent that "Sinead has had a long friendship with Steve which has now blossomed into a relationship. She now believes this is the perfect basis for a marriage and a more settled stage in her life."
The marriage took place in in Europe as she plays in Lucerne, Switzerland on Saturday night as part of an acoustic tour.
The band is herself, new husband Cooney and fellow musician Kieran Kiely.
Australian-born Steve Cooney has been a member of Sinead O'Connor's band for the last four years as guitar player.
Before joining Sinead's band he was a key member of Stockton's Wing, for whom he played bass, and was also a member of duo 'Cooney & Begley' with musician Seamus Begley which played many venues in the Kerry Gaeltacht (Irish speaking) areas.
O'Connor has been wed twice before. Her first marriage was to writer John Reynolds,
They have a son Jake (23) together. She then had daughter Roisin in the 1996 with journalist John Waters.
In 2001 she married journalist Nick Sommerland but they split less than two years later. She had a son Shane with folk musician Donal Lunny in 2004.
She was seeing Mary Coughlan's ex husband, American Frank Bonadio, but they split earlier this year.