The 32-year-old, who had won a silver in super-G and a bronze in downhill earlier in the week, beat Ivica Kostelic on a tricky slalom course set by the Croatian's father to collect the fifth Alpine skiing medal of his Olympic career.
Switzerland's Silvan Zurbriggen, a distant cousin of former Olympic champion Pirmin, took the bronze medal on a day when bright sunshine and gleaming pistes were matched by equally brilliant skiing.
"I skied my ass off," gasped Miller, the words gushing out of his mouth in a rapid flow after he had thrown everything at the hill.
He had finished the downhill in seventh place after a mistake and, with a daunting 0.76 seconds to make up, threw caution aside.
"I dug deep," Miller added, the stars and stripes on his race suit matched by the flags waved by a crowd on tenterhooks and roaring him on.
"I was so tired. This was probably my best chance to win, but it took a huge amount of mental stamina.
"To execute the race the way I did today is something I will be proud of for the rest of my life."
Team mate Ted Ligety, who won the old-style combined in Turin four years ago ahead of Kostelic, paid tribute to his compatriot who completed his transformation from the flop of 2006 to become the first US skier to win five medals.
"The combined is tailor-made for Bode," he said. "He is one of the world's best downhill skiers and he has had moments of brilliance in the slalom and showed it today."
Norway's Aksel Lund Svindal, who had led after the downhill part of the event, had no alternative but to attack the piste and hope for the best. He lost the bet.
The last of the leaders out of the start hut, the newly-crowned super-G champion saw his bid for a second gold, and third medal, of the Games disappear when he lost his rhythm and skied out.
"It happens, it's part of the Games," he said.
"No-one wins anything by being safe. In slalom you can't defend anything, you just have to get after it."
Kostelic, the brother of retired multiple gold medallist Janica, was delighted to repeat his Turin silver despite again losing out to an American.
"It's totally different to be at the Olympic Games and be one of the favourites," he said. "This is so important for me and my family. This is just the top."
Britain's Ed Drake was 29th, his highest finish yet in the Winter Games.
The 24-year-old from Kingston-Upon-Thames, who finished 38th in the downhill on Monday and 32nd in the Super-G on Friday, said: "I can't complain about that. I would have settled for a top-30 before. I would have liked to get into the top-30 on the speed run, but I missed that by twelve hundredths of a second.
"I didn't expect too much from the slalom. It was my first competitive slalom of the season and I'm not a slalom skier, but I put in a half decent performance," he said.
Place of birth: Franconia, New Hampshire, United States
Residence: Franconia, New Hampshire, United States
Previous Olympic results:
2x silver, 2002 Winter Olympics, Giant Slalom & Combined
2x gold, 2005 world championships, downhill & super-G
2x gold, 2003 world championships, giant slalom & combined Silver,
2003 world championships, Super-G 2x champion,
2007-08, 2004-05 World Cup, overall Runner-up, 2002-03 World Cup, overall
Miller finally grabbed an elusive gold medal in Vancouver after years of promise and near misses. A double silver medallist in Salt Lake, he went to the Turin Games as a contender in five medal events but failed to score a podium finish.
His five Olympic gold medals is the most won by an American Alpine skier.
He started skiing at age three. He grew up in the woods outside Franconia in a cabin without electricity or indoor plumbing and was home schooled until Grade Three.
Once a high school tennis state champion, Miller is one of the sport's most charismatic and talented racers. His reckless do-or-die approach to the sport has won a legion of fans around the world.
He revolutionised the skiing industry when he started to use hourglass-shaped skis.
He lost his 2003 world championship combined gold medal after using it to hold up the toilet seat at home. He lost his 2005 World Championship super-G medal after it was stolen from his jacket but it was later returned.
In an interview with American television program 60 Minutes, Miller admitted to skiing "wasted", sparking scorn from US ski officials and politicians.
Following years of awkward co-existence, Miller split from the US ski team after the 2007 season to race independently, financing his own Team America.
The gamble proved a huge success with Miller winning six World Cup races in 2008 and his second overall title.
In 2009 he disbanded the team and announced his intention to return to the US ski team for one last chance at winning an Olympic gold medal.