The Frenchman was this week named as one of Lotus Renault's drivers for the 2012 season - three years after failing to fire in his debut season.
Grosjean believes his performances in the GP2 series and practice sessions in Abu Dhabi and Brazil played major roles in the team's decision.
The 25-year-old admits he is in dreamland after being handed a seat.
"A Formula 1 driver! Wow! It's a dream come true," he said on the team's official website. "It's difficult to find the right words to describe what I feel.
"It's quite simply fantastic and I can't wait to be at the start of the Australian Grand Prix on March 18 next year."
Grosjean is coming off a successful season in the GP2 Series, winning five races en route to the Championship honours. He also spent some time behind the wheel of the Renault in Abu Dhabi and Brazil after being handed first practice duties.
"I think that my season in GP2 helped me get the seat as a nominated driver, because what people expected from me was to show that I'd grown up and matured - that at that level I was already capable of being a team leader," he said.
"The two free practice sessions in the Abu Dhabi and Brazilian Grand Prix were also a kind of real live assessment to see if I'd improved, if I was able to cope better with pressure and if I was still as quick.
"All these factors added to my two GP2 titles with DAMS were certainly major influential factors that helped me get the drive with LRGP in 2012."
It is exciting times for Renault as Grosjean will line up next to former world champion Kimi Raikkonen and the Frenchman feels they will make "great pair".
"I'm beginning to get used to having a world champion as team-mate," he said.
"After Fernando Alonso, now it's Kimi Raikkonen. But it's a real stroke of luck as you learn a lot from these people. And as we've got the same car matching their level is proof of the quality of the driver."
He added: "Raikkonen is a great driver, he's got nothing to prove anymore and I'm delighted to have the opportunity of working with him.
"I believe that I too can bring something to the team with my understanding of the Pirelli tyres. He knows the ones in rallying but not those in Formula One. I think we'll make a great pair and that speed will be one of the major pluses of the team."