Grant (26) has signed a contract with top club Montepellier, and leaves tomorrow for the south of France.
Grant said the French side had suffered a couple of injuries in the loose forwards and needed cover.
The contract was until the end of this season and Grant hoped he would play well enough to pick up another contract next season.
''I've been looking for a while, so when this offer came along it was not a hard decision to make. It was good to finally have something solid signed and I'm looking forward to getting over there,'' he said.
No 8 Grant will join a club flying high in the French Top 14, sitting second on the table, just behind Toulon on points differential. It is also involved in the Heineken Cup, and has a big match in a couple of weeks against Leicester.
The South Otago High School product said the deal had come together quickly and had only been completed over the past couple of days.
Grant played 57 games for Otago, after debuting in the 2006 season. He was in and out of the Otago team over the first few years but in the past couple of seasons has become a mainstay of the side and impressed with his play.
But he never won selection in the full Highlanders squad - which has been questioned by many people - and Grant believes he never got a fair go from the franchise.
Grant has been in wider training squad groups for a couple of years but has been overlooked over the last two seasons when he has played well for Otago.
The University A loose forward said he felt let down after training with the Highlanders at the start of last season, called in as an injury replacement in January and February this year.
''I felt, after being with the side for five weeks at the start of the year, I deserved a bit more feedback than I got.
''All I got was one text message saying, `Don't come Monday'. I thought I deserved a bit more than that.
''I never got any feedback. I would have appreciated just a couple of things to tell me what to work on. That is how you grow as a player.''
There had been suggestions he had been promised a position in the Highlanders wider training group for the 2014 season.
Grant said he was in contention for a wider training group spot but had never been offered a position.
''I then decided to take myself out of the running for that position.''
Now he had tied up a contract with Montpellier, he would put that disappointment behind him and move on, he said.
He was excited to be heading to France, where he will be in a team with former All Blacks Rene Ranger and Anthony Tuitavake, Canterbury prop Paea Fa'anunu and former Crusaders back Hamish Gard.
Montpellier also has French internationals Nicholas Mas (prop), Fulgence Ouedraogo (flanker) and Francois Trinh-Doc (first five) in their squad.
For the time being, his career with Otago is over, and Grant said lifting the Ranfurly Shield this season was the undoubted highlight.
''We had our awards night the other night and they showed a few shots of that game. It was great to think back to that and what a great time it was.''
Grant's partner, Monique Bates, may head to France at the start of next year.
