The 26-year-old scrum-half was capped once against the All Blacks when the Lions toured New Zealand four years ago but has since fallen behind Edinburgh's Mike Blair in his country's pecking order.
"I believe it's the right time to come back to Scotland," said Cusiter, who currently has 39 Test caps to his name.
"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."
Cusiter left Scotland to sign for Perpignan in 2007 after the closure of his previous side, the Border Reivers. He believes his time in France has helped him develop as a player and that Glasgow's recent form, especially in the last two rounds of the Heineken Cup, means he will be joining a side making equally impressive developments.
"Playing in France has been a fantastic experience and I've learnt a lot," added Cusiter.
"I now look forward to a successful end to the season with Perpignan before returning to Scotland in the summer.
"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.
"I'm joining an ambitious club with huge potential and I'm excited about the challenges."
Cusiter's new coach, Sean Linneen, has worked with the No9 at previous club Boroughmuir and the Glasgow boss is clearly a big fan of his high-profile signing.
"Chris is a world-class player who I've admired for many years," said Linneen.
"The experience he has from playing in France cannot be underestimated.
"This signing shows that Glasgow are moving in the right direction and I can't wait to see Chris in a Warriors shirt next season."