The 29-year-old produced a perfectly-timed race to leave his rivals behind and claim Team GB's sixth gold medal of the day.
Farah told BBC Sport: "It's never going to get any better than this, it is the best moment of my life.
"It was just amazing, my legs were getting tired but the crowd gave me a huge lift. I want to thank everyone associated with me."
Farah must now decide whether to attempt a double at London 2012 and run in the 5,000m next week.