Muirhead and her team of Anna Sloan, Vicky Adams and Rhiann Macleod cruised to a 10-3 victory over Canada in the final.
Muirhead said: "We gave them nothing and that's the way we wanted to play. We didn't miss anything, we placed the stones exactly where we wanted them."
"To win it four times feels pretty good, each time feels just as good as every other time, but this is special."
Oskar Eriksson and his Swedish team of twin brothers Alexander and Kristian Lindström and Christoffer Sundgren, won the men's title 6-5 in a tight final against defending champions Switzerland.
Eriksson said: "It feels awesome, I am so relieved now to have the gold medal, finally".
"We didn't play so good at the start.
"Me and Kristian missed a couple of shots, we had some pressure on us."
March 2011: Curling Championships return to spiritual home