As their rivals ran into a variety of problems, Mikkelsen and co-driver Ola Floene kept going to achieve a second consecutive win in their Skoda UK Motorsport-backed Fabia S2000.
It was enough to give them the crown by just 1.5 points from Skoda team-mate Jan Kopecky - the Czech scored higher across the season but fell back when dropped scores were taken into account.
Norwegian Mikkeslen said: "To become IRC champion is such a fantastic feeling, the likes of which I have never felt before. Five years ago a knee injury forced me to quit my alpine skiing career and since then we have put so much effort into my rallying, not just by me, but also by the people around me. To give this title back to everyone who has put so much faith in me is incredible.
"It's been a tough season, which didn't start so well in Monte Carlo but which has got better and better. We've had a fantastic second half of the year and, wow, to finish with a win in Cyprus and the IRC drivers' title - I can hardly believe it has happened. It's like a dream.
"The last three stages of this rally were the longest of my life and I was imagining so much noise in the car that I've never heard before. Crossing the finish line was very emotional and I was crying like a baby!
"I'd really like to thank everyone at ŠKODA UK Motorsport and ŠKODA Motorsport for and giving me this opportunity this year. It's a special moment for everyone."
Robert Hazelwood, Skoda UK Director added: "What an incredible end to the 2011 IRC season. I'm personally delighted for Andreas and Ola on their fantastic season, which has resulted in two wins and the IRC drivers' title. Their championship win is richly deserved, as they've been getting faster and faster throughout the year and held their nerve under pressure - and nowhere more so than in Cyprus. Andreas is a very mature and quick driver and it didn't take him long to achieve his first major rally title. Many congratulations from everyone at Skoda UK."
Click on this link for the final IRC points table http://www.ircseries.com/html/uploadedfiles/pdf/results_2011_D_IRC.pdf