So two devastating and embarrassing moments at past Olympics really don't mean that much to the U.S. shooter, even if he did lose gold medals by shooting at the wrong target and having his gun fire accidentally.
When shooting events begin Saturday at the London Games, he has another chance. And this time, Emmons plans to use what he learned from his illness and his Olympic disasters in 2004 and 2008 as an asset.
"The fact of the matter is I have been through more stuff on and off the range than anyone else standing on that firing line, which is a huge advantage," said Emmons, 31, who also has been dealing with a bad back in recent months. "I know if I'm able to physically hold the gun still enough I think I can be competitive."
Emmons' saga began at the Athens Games in 2004, when he had a big lead going into the final shot of 50-meter, three-position rifle, in which competitors shoot from kneeling, standing and prone positions. But he accidentally fired at the wrong person's target on his last attempt, earning no points and falling out of medal contention completely.
After the mishap, he carried himself with grace, almost shrugging it off as just a weird thing that can happen. Later, he was hanging around having a few beers with friends when Katy Kurkova, a female shooter from the Czech Republic, came up to offer condolences.
They ended up hitting it off and got married in 2007, proving that good can come even after a crushing defeat.
Four years later at the Beijing Games, his wife was in the stands when he again lost the gold in the same event. Emmons was ahead going into the final shot. But again, there was a foul-up. His gun accidentally went off while he was still lining it up. The crowd gasped audibly and Katy Emmons looked stunned as her husband fell out of the medals for a second time. He finished fourth.
He didn't leave Beijing without a medal, taking silver in 50-meter prone rifle. He'd won gold in the same event in Athens in 2004.
Emmons' biggest battle started in September 2010. Shortly after his cancer diagnosis he had his thyroid removed. He was out of training for several weeks, but competed in a small event three months after his surgery, U.S. team shooting coach Dave Johnson said.
He gets checkups twice a year and will be on medication for the rest of his life. Early in his treatment, Emmons and his doctors struggled to find the right dosage. The medicine affects a person's metabolism, making it tough at that stage to train consistently, Johnson said.
"That's been a challenge," Johnson said. "He's had to adjust."
Emmons says he's glad to be on the other side of his medical hurdle.
"As far as I know I'm clean," he said. "My hormone levels ... are right where they need to be. I feel good."
Johnson has known Emmons since he was 15 and seen him mature through the Olympic errors and the cancer.
"He has a very healthy view of sport, and I think that will carry him through," Johnson said. "He wants to get this done."
Emmons will compete in London in the 50-meter, three-position rifle and the 10-meter air rifle. His wife also is back shooting for her homeland after winning gold in 10-meter air rifle and silver in the 50-meter, three-position rifle in Beijing.
The two also have a child, Julie, who was born in 2009. Their daughter will be staying with her mother's family in the Czech Republic during the Olympics so that mom and dad can focus on their competitions.
Fatherhood, Emmons said, brought with it another discovery: There is "something way more important" than sport.
He's been able to put his past Olympic mistakes in perspective. Little would have been made of his blunders if they hadn't happened during the Olympics, he said.
"If it's in a World Cup competition, it's no big deal, nobody talks about it," Emmons said. "But, of course, the Olympics everyone talks about it."
And that's still happening. He's asked all the time about having twice lost gold, which has, along with actually losing the medals, brought him "a thicker skin."
"All those things have made me a much wiser person, a much smarter person and I appreciate a lot of things now that maybe I didn't eight, nine years ago," Emmons said. "I honestly don't worry about too much anymore."