Known primarily as a winger, Kilbane is something of a dead-ball specialist and has chipped in with his fair share of goals for the Baggies.
The Preston-born player is 6ft tall and weighs 12st 10lb, giving him a physical presence which makes him a real handful for defenders. He trained with his new team-mates yesterday before undergoing a medical, and the transfer finally went through in the evening.
The Sunderland manager, Peter Reid, said: "He's a quality player who put in exceptional performances for the Republic of Ireland in the [Euro 2000] play-offs."
Kilbane, who began his career as a trainee at Preston North End, added: "The club is going places and is on fire at the moment. It is a massive club and I'm really looking forward to playing here."
Kilbane would have been out of contract at The Hawthorns at the end of next season, but it became clear in recent weeks that he was unlikely to commit himself to the Midlands club again.
His arrival at the Stadium of Light presents Reid with a series of interesting choices. The Swedish international Stefan Schwarz has been playing wide on the left after switching roles with Gavin McCann, and both men have made themselves fixtures in a side which is now lying fourth in the Premiership.
But the signing of Kilbane seems to have confirmed the eventual departure of the Scottish international Allan Johnston. He has not played for the Wearsiders all season after being transfer-listed, along with Michael Bridges and Lee Clark, for refusing to commit himself to a new deal last summer.
Johnston, who has just returned from a two-month loan spell at Birmingham City, is out of contract at the end of the season and is available on a free transfer under the Bosman ruling.
Reid's no-nonsense approach to transfers initially caused one or two raised eyebrows, but the recruitment of Schwarz, Steve Bould and, later, the French midfielder Eric Roy, plus a fearsome start to their first season back in the top flight, soon calmed any fears.
Reid, the former Everton and England midfielder, has always maintained that he wanted to strengthen his squad, but has refused to be held to ransom. He has made something of a habit of picking up quality players at knock-down prices
The Irishman's first opportunity to sample the atmosphere at the Stadium of Light in a Sunderland shirt could come on Saturday, when his new side takes on Southampton in the Premiership.Reuse content