Career Highlights: A former discus thrower, Johnson has blossomed into the United States’ best in the hammer throw over the past two years, winning his first national title in 2011 and again taking the top spot at the Olympic trials to earn a spot in London. He also won gold at the 2011 Pan American Games with a meet-record toss of 79.63 meters, and became the first American since 2000 to break 80 meters last year. While Johnson may be a long shot for a medal in an event dominated mostly by Europeans - he didn't make it out of the qualifying round at last year's world championships - he’ll have a special motivation to perform well in London. “My grandparents have been to every Olympics since 1976, I think,” he said, “and now they get to see me there.”