The Almondvale club had been negotiating with the League of Ireland side for almost a week and have now struck a deal which is thought to include clauses based on appearances and future transfers. 
Hoolahan should be available to Paul Lambert for Livingston's Tennent's Scottish Cup tie against Alloa a week tomorrow.
Pat Fenlon, the Shelbourne manager, was disappointed to lose Hoolahan but insisted Livingston were landing one of Ireland's most technically-gifted players.