The 31-year-old appeared in 17 league games for the Scottish outfit in 2013/2014, helping them to their first ever RaboDirect PRO12 final against Leinster at the RDS on Saturday.
It would not be the fairytale ending to five years back in Glasgow for Cusiter however as the Irish side triumphed 34-12 while the scrum-half was also forced off early in the second-half after taking a knock to the head.
He will now move south of the border to Sale Sharks, but after a strong campaign - which saw Glasgow set a club record nine-match winning run - the Scotland international insists he is leaving with plenty of positive memories.
"This has been my most enjoyable season" he told the Scotsman. "I have got a new lease of life and enjoyed rugby. I will leave with lots of fond memories and will be watching the boys when I can. It is a great club.
"There was one bad season but, apart from that, it [Glasgow] has gone in the right direction. This season has just gone to another level.
"That home semi played in front of 10,000 people, the interest around Glasgow, the taxi drivers chatting to you about how well Glasgow are doing, the people in the street.
"By beating the big teams regularly we have gone to the next level. I hope they continue that."
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