He habitually defied authority, once kicking his high school principal. When he was 17 he stole a car, and a juvenile judge gave him a choice: several months in jail or probation on the condition that he attend the Mission Ridge Academy, a ski school at Wenatchee, Wash. He chose the school and got up at 5 a.m. to wash dishes at a Big Boy restaurant to pay his fees.

When reporters later revealed the car-theft incident, Johnson blamed his father, saying he had leaked the information to the news media in the belief that people would respond sympathetically to the idea of a poor boy recovering from shame to beat rich athletes in an elite sport. Sure enough, a London tabloid proclaimed Johnson’s victory with the headline “Car Thief Steals Gold in Sarajevo.”

In 1979, Johnson received a scholarship to attend the Alpine Training Center in Lake Placid, N.Y. Wind tunnel tests there discovered that he had aerodynamic gifts that gave him a 3 to 5 percent advantage over anyone else who had taken the test. Most skiers have to work at “the tuck,” the position used by downhill skiers: torso hunched over bent knees, fists in front of the face, poles pointed straight back. But it seemed to come naturally to Johnson, who was compared to a gravity-powered rocket.

He was named to the national team, but was dropped in 1982 for refusing to run or lift weights. The next year he dominated the Europa Cup tour, skiing’s top-rung minor league. He was the first American to win the downhill and overall titles in the series.

He started 1983 slowly on the World Cup circuit, finishing 26th, 42nd, 20th and 23rd in the year’s first downhill events. Then came his breakthrough, in spectacular fashion. In a World Cup race in Wengen, Switzerland, in January 1984, Johnson seemed to lose control at 70 m.p.h.: one ski went right, the other left. He balanced on one ski for a fraction of a second and shot a few yards off the track, but he regained control as if nothing had happened and went on to his first World Cup victory.

It set the stage for the Olympics. The Swiss and Austrian skiers who dominated the sport were openly contemptuous of the downhill run at Sarajevo. “This is basically a course for 8-year-olds,” said the Austrian Franz Klammer, the world’s best downhill racer in the mid-1970s. If Johnson did well, he said, it was only because he could rocket straight down and would not have to turn much.

The two were exemplars of two different styles. If Klammer was the Gene Kelly of downhill skiing, powerfully athletic on steep, icy courses, Johnson was Fred Astaire, graceful and fluid and landing lightly off a jump. Johnson launched his gold-medal-winning descent by first pointing his ski pole down at the course unfolding below him, a gesture reminiscent of Babe Ruth’s with a bat in baseball lore. Klammer finished a distant 10th and said he was “surprised.”