Cusiter, 26, who captained the Border Reivers in season 2006/07 before joining French Top 14 side Perpignan, said: "I'm joining an ambitious club with huge potential and I'm excited about the challenges that lie ahead.
"Both Scottish pro-teams have been getting good results recently and Glasgow have made their future intentions clear with some great performances, especially with the recent win over Toulouse.
"Playing in France has been a fantastic experience and I've learnt a lot. I now look forward to a successful end to the season with Perpignan before returning to Scotland in the summer.
"I hope to bring the experience I've gained over the last two seasons to an already very talented Glasgow squad.
"I believe it's the right time to come back to Scotland. I'm looking forward to earning a starting place for Glasgow which, in the long run, may also help my international aspirations as we look forward to the Rugby World Cup in 2011."
Warriors head coach, Sean Lineen, who coached Cusiter as part of the 2003 Premiership title winning Boroughmuir side, added: "It's fantastic news for Glasgow Warriors and Scottish Rugby.
"Chris is a world class player who I've admired for many years. The experience he has from playing in France cannot be underestimated.
"Today's signing shows that Glasgow are moving in the right direction and I can't wait to see Chris in a Warriors shirt next season."
Since his international debut in 2004, Cusiter has gone onto win 39 caps for Scotland and is part of Frank Hadden's squad currently preparing to take on reigning RBS 6 Nations Grand Slam champions, Wales, at Murrayfield on Sunday 8 February (kick-off 3pm).
In 2005, Cusiter represented the British & Irish Lions on six occasions, including as a substitute in the pre-departure Test against Argentina in Cardiff, a match in which current Warriors fullback Bernardo Stortoni started for the opposition.
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland