The Perth-born skip has spent the last 10 days insisting she was having "super fun" and was "super happy", without giving any indication that she actually was.
Studying her during a game in a bid to ascertain her state of mind will have left most observers disappointed. She has been as hard to read as a work by Fyodor Dostoyevsky.
Not so yesterday, as Muirhead, hitherto a picture of concentration was reduced to tears, to match those of her team-mates. "It's just a huge relief," Muirhead said, as the emotion was finally released. "Maybe I come across quite stern faced and focused but inside I'm not as hard as everyone likes to think.
"It's tough out there, mentally and physically. I'm just so happy, relief is probably an understatement. I couldn't think of what it would have been like to walk away without a medal around my neck.
"That shows what great athletes we are, you have to learn to lose before you can win and get back up from a defeat. To lose a semi-final at the Olympics and then come back and play for bronze is extra tough. We regrouped and came out fighting. I'm mentally buzzing, it's been a constant rollercoaster. We've had some tough losses and great wins, and many of the games have come down to last end, last stone.
"To end on a high makes it even better and to win it with four of my best friends feels so special."
Scottish rower Katherine Grainger, someone who knows a thing or two about struggle before triumph, sent Muirhead and her team - Anna Sloan, Vicki Adams and Claire Hamilton - a note of support before their bronze medal match with Switzerland. Andy Murray tweeted his backing, and Sir Chris Hoy got in touch. However, it was coach David Hay who played the major role in rebuilding confidence following defeat by Canada - who won gold against Sweden yesterday - in the semi-finals.
Hay has the same reassuring air of confidence as his brother Mike, Great Britain's chef de mission in Sochi and the man who guided Rhona Howie (nee Martin) to gold 12 years ago today in Salt Lake City.
"Dave has been life changing to us," said Muirhead. "He brings so much experience. After the semi-final defeat he was fantastic, he said everything just right and we responded with a tremendous team effort."
Howie won her Olympic gold aged 35, which means Muirhead could have three Olympics ahead of her and, provided the team stay together (Sloan skipped her own rink to the Scottish title in 2011), then the future looks exciting, even though they will not be defending their world title in New Brunswick next month.
"Ever since I was a young girl one of my main goals was the World Championships but when you win an Olympic medal it's just as special," added Muirhead.
"We're a young team with a lot of time ahead of us. We're the youngest team here, our average age is 23 and I believe we've got a really big future.
"Curling gets a lot of attention every four years and for us to increase that, we've got to win medals. This is just the start for us."