recovered from an early puncture to score points in his final outing with the Mercedes team.
In an incident-packed race, Schumacher fell to the back of the field in the opening laps but climbed to sixth before being passed by title-bound fellow-German, and good friend, Sebastian Vettel.
"I think it's a nice ending," he said. "I'm finishing off and he's (Vettel) clinching his third title. I'm very proud of him, he's a good friend of mine.
"My emotions are under control at the moment, maybe later having a drink and hugging the mechanics it'll become more sentimental but I'm looking forward to life after Formula One now.
"It's been a pretty big challenge in this race because obviously I had the puncture and was at the back again... It took some memories back to 2006 when the same thing happened to me.
"Luckily I have the nature of not giving up and always trying to find a solution, and it worked out. In a way it does remind me of 2003 when I had a similar struggle and just managed by a point to win the championship."
He smiled as he looked back on his thrilling fight with 2007 champion Kimi Raikkonen of Lotus during the race.
"People are here to see a show, so you might as well put one on," added Schumacher.
"Give it a go and give it the maximum. I was having a go, and at certain moments you need to accept that there isn't the space and admit defeat."
He added that he had enjoyed his "second career" with Mercedes.
"It's been a beautiful time. Lots of exciting moments we shared, and lots of tough moments. The most incredible thing in a way is that I felt a lot of support in these last three years and they have been the most difficult years for me. But the fans have always been behind me."
For Schumacher's fans, as in 2006 when he first retired, there was an air of disappointment about his exit from the sport because it came not by choice, but circumstance.
When he retired after the Brazilian Grand Prix six years ago, it was because Ferrari had made clear they were signing Raikkonen from McLaren.
This time around, it was another McLaren driver, Lewis Hamilton, who had to be accommodated by the German's departure as Mercedes build for the future.
"It's a strange sort of coincidence that I've ended my Formula One career now in seventh, which was my first ever qualifying result at Spa-Francorchamps," said Schumacher.
"It also occurs to me that I was driving with the number seven on my car today and that I have seven world championship trophies in my cabinet.
"Even under these difficult conditions, my final Formula One race was tremendous fun, and I would once again like to thank the team and all my fans for their support over the past years. I've enjoyed the time we've spent together very much indeed."
After 307 races, few drivers are without the bruises to show as proof of their scraps with the man Mercedes team chief Ross Brawn this week described as "probably the best Formula One driver of all time".
Brawn was with Schumacher at both Benetton and Ferrari and is widely regarded as the architect of his seven championship triumphs -- a haul that is unlikely to be challenged in the near future.
"In terms of results, his second spell in Formula One hasn't been as special but it has been so for all of us who have had the privilege of working with him," said Brawn after Sunday's race.
"It has been a real honour for all of the boys and girls at our team, and working alongside Michael gives you a real understanding of why he is so special and has achieved seven world championships."
Brawn had paid a glowing tribute to Schumacher on the eve of the race.
"Having worked with Michael for the majority of the 21 seasons of his career, I feel that he is one of the greatest, if not the greatest, Formula One driver of all time."