The 19-year-old will drive with the Dandenong-based team on a multi-year deal.
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McLaughlin's Dunlop Series success makes him the youngest ever champion of the class.
To top off the year, McLaughlin was handed his solo V8 Supercars debut in Sydney, replacing Fujitsu GRM driver Alexandre Premat who was ruled out of Sunday's race due to being dehydrated in Saturday's hot 250km race.
McLaughlin finished a sensible 17th place in Sunday's race.
GRM team owner Garry Rogers says he is pleased to have secured the young charger.
“We've been keeping an eye on Scott for some time and his on-track approach has been very impressive,” Rogers said.
“He's a level-headed young man who has shown great race craft and I was very impressed with his endurance racing this year, while his Dunlop Series championship speaks for itself.
“I think Scott will gel well with our boys and his experience driving the prototype Car of The Future last year will also be advantageous going forward.”
McLaughlin is ecstatic about his future, having set himself the goal of a full-time championship seat for 2013.
“This is what I have been working towards since moving up from karts in 2010 and the championship in my third year was always my focus, so to be picked up by Garry and his team and to be able to continue my relationship with Fujitsu is just fantastic,” McLaughlin said.
“Garry is a ‘no BS' type operator and the whole GRM environment will see me well prepared going into the 2013 season. I've had the most amazing year this year so this just caps it off perfectly and can't wait to get started with the team just as soon as I can.”
McLaughlin will complete the final year of his trade apprenticeship (fabrication).
The New Zealand-born, Gold Coast-based driver will get his first laps in one of Garry Rogers Motorsport's Car of the Future Commodores at Winton this Monday.
McLaughlin's team-mate is yet to be confirmed, with Frenchman Alexandre Premat in negotiations with the two-car Holden team to remain there in 2013.