"What an incredible finale, what a thrilling finish!" the former Ferrari driver said in a statement on his Web site (www.michael-schumacher.de) after Raikkonen and Felipe Massa took the first two spots for Ferrari to clinch the championship.
It was a remarkable comeback by the Finn, who had trailed Britain's Lewis Hamilton by 17 points with two races to go.
However, Raikkonen earned 20 points and overtook both Hamilton and McLaren team mate Fernando Alonso to win the championship by a single point.
"I was so, so happy to see Kimi and Felipe leading the way across the finish line," said Schumacher, who was team mates with Massa last season.
"I've always believed that you should never, ever give up and you should always keep fighting even when there's only a slightest chance.
"Congratulations to Kimi and all our guys -- that was a super performance," the German added.
Schumacher, who retired at the end of last season as Formula One's most successful driver, is now a technical advisor for Ferarri.
He went to several races this year but preferred to watch the finale from home, which he said he now regrets.
"In retrospect, the only unfortunate part is that I wasn't there myself," Schumacher said.
"I would love to have celebrated with them all. But we'll make up for that as soon as possible, and I'm really looking forward to that."
Schumacher, 38, won five consecutive world championships for Ferrari between 2000 and 2004. In 2003, he clinched the championship in the last race, getting the points needed to fend off the challenge of Raikkonen, who was driving for McLaren.