A run of bad luck has seen Kovalainen lose valuable points
McLaren have ended speculation about Heikki Kovalainen's future by confirming he will race for the team alongside Lewis Hamilton in 2009.
The 26-year-old Finn was pleased with the decision and said he was ready to commit to the team.
"I want to be a successful with them - hopefully, we can announce at some point in the future that I will stay for many years to come," he said.
"I'd be happy to finish my career with this team, to be honest."
Team-mate and world championship leader Lewis Hamilton said he was delighted with the announcement.
"It's great news - the atmosphere in the team is fantastic, and a lot of that is due to Heikki being there and how we have worked together," said the Briton.
"So I welcome it, and I really hope he stays for longer."
The Finn, 26, has collected 28 points so far in his debut season for McLaren but the team believe he can progress.
McLaren chief executive Martin Whitmarsh added: "He is a brilliant young racing driver.
"But there's no magic in Formula One and we still need to work with Heikki to extract his full potential."
Kovalainen joined McLaren from Renault for the beginning of the 2008 season with Fernando Alonso moving in the opposite direction.
After a progressive season with Renault, the Finn was expected to provide a tough, but more amicable, team-mate for Hamilton at McLaren.
However, after 10 races, Kovalainen trails Hamilton by 30 points in the drivers' standings to see his own title chances fade.
A topsy-turvy season has seen the Finn perform well in qualifying, capturing a maiden pole at Silverstone, but struggle to make his grid positions count.
Kovalainen's only podium of the season has come with third place in Malaysia and the Finn has been working with the team's engineers to improve his set-up ahead of this weekend's Hungarian Grand Prix.
But McLaren, who were rumoured to be interested in Williams's Nico Rosberg, have chosen to stick with Kovalainen as they look to build a period of stability at the team after a 2007 season upset by strained team relationships and the McLaren-Ferrari spy row.
Whitmarsh added: "We welcomed Heikki on board at the start of the year.
"He is under contract to McLaren Mercedes and will race for us in the 2009 season."