The ex-Hibernian winger has joined the Airtricity Premier Division side for the upcoming season
Galbraith had been on a free transfer after being released by Pat Fenlon's side last month, and welcomed the move to the First Division champions.
"I've heard about the passion of the supporters here and I'm looking forward to playing in front of them at Thomond Park, which will give everyone around the club a great lift," Galbraith told the club's official website.
New Blues boss Stuart Taylor was very pleased with his new arrival, saying "Danny is a fantastic signing for the football club and shows the ambition of the club that we’ve signed a player of Danny's pedigree.
"He brings a different dimension to our squad and will be an essential part of the new look at Limerick in terms of philosophy, ideas and mentality. He'll be a great addition for the young players to learn from and his presence alone has given the dressing room a lift already."
Meanwhile, Limerick's opening home game of the season with Cork City has been moved to March 10 for television coverage.
It will be shown live on RTE along with Shamrock Rovers v St Patrick's Athletic on March 15, and Shelbourne v Shamrock Rovers on March 24.